Computer Tutorials

recover your Windows Administrator Password in just few seconds using OPHCRACK software
just download the ISO file, burn it in a CD and boot your pc using the CD with ophcrack.

DOWNLOAD HERE:
http://station-d.blogspot.com/2008/09/ophcrack-windows-password-recovery.html

Procedure used to recover data from a quick-erased CD-RW disc

1. Make a file of exactly the size of the cdrw disc's capacity (650MB in my case).
(this step may not be needed)

2. With Nero I created a new project and added the file to it so that I have the disc filled. I gues you can also fill up the disc with other files.
The reason why I fill the disc is because I want Nero to make a session that uses the entire disc. Like I wrote earlier in this thread I experienced that my CD-Drive refuses to read off the disc beyond the session's boundaries. When you quick-erase a disc there is no session anymore so the drive will not read at all. Burning a new session will overwrite the data and burning only a small session will NOT make the drive read the other data that is still on the disc.
The reason why I used the one big file is so that I could later on recognize which part of the disc was overwritten by this file because this file contained all zeros (0x00).

3. I pressed burn and selected disc-at-once. Then while Nero was burning the leadin I pressed cancel. My CD-Drive finished writing the lead-in and Nero reported an error.
This is what was accomplished however: Now the disc contains a session that says that the used disc size is the complete disc. Nero did not get to writing file because I cancelled it. Good thing because I don't want Nero to write any files because my old data will get overwritten!
I gues it works the same with different writing software. Another method that I used during a test was simply press the reset button of the computer when the burning software was done with writing the lead-in and started with the files.

4. I had to restart the computer after cancelling burning.
With the cdrw disc inserted I saw in "my computer" that windows recognized that the disc was 650MB, clicking on it gave an error. Good so far!

Now with IsoBuster you can extract the sectors from a disc to a file. This is what I did.
I gues that if you have data-recovery software at this point it will be usefull because now (if all went well;)) the CD-Drive WILL read data from the entire disc. Anyway, I used ISO-Buster because the files that I needed to recover where a bit odd for nowadays (.XM, .S3M, .MP3):
In IsoBuster I had to do several steps:

Step 1: Find out from and to which sector the drive will read
By choosing "Sector View" you can look at any given sector.
Here I found out what the first and the last sectors where that are readable. (Hint I used the method for the old game: "Gues a number below 100, I'll tell if it is higher or lower than what you gues")
Step 2: Extract the actual sectors
By choosing "Extract From-To" you can extract any given range of sectors to a file. My disc was a data-disc so I choose the first extraction type "User data, 2048 bytes/block...".

In the end I got a .tao file which was about 650MB. I ran several programs on it to look for files inside a file by searching for file-header-paterns:
1. Multi Ripper 2.80 (for DOS, for the .XM files. It does many other file formats as well (jpg,png, bmp,wav,etc,etc +100). Try google with this query: Multi Ripper 2.80. I still had the file from good old days but I saw several good search results)

2. Winamp for mp3.
Winamp will scan any file when you give it the extension .mp3 and play it as one big song (so I renamed the .tao file to .mp3). I used the discwriter to get a .wav and the Adobe Audition to manually cut and save my songs. I looked at the MP3 file format and it is hard to find an mp3 file in a big file because it has no clear header just a bunch of mpeg-frames in most cases for me . A lot of my files had no ID3v2 or ID3v1 tags... But after a couple of hours I recovered everything.

Finally a list of used stuff:

Software:
- IsoBuster v1.5
- Nero 6.3.0.3
- Multi Ripper 2.80
- WinAmp v5.02
- Windows XP Pro NL (patched up)

Hardware:
- NEC DVDRW ND1300A 1.06

Disc:
- some old 4 speed cdrw

Here's a DOS trick for Windows 9x, that will reset (delete) your motherboard's BIOS password (aka CMOS password) without any need to open up your computer to remove the battery or mess with jumpers.

This method can come in very handy in the event you ever lose and forget your BIOS password or if you acquire used computers where the unknown previous owners had BIOS passwords set (in fact, this happened to me long ago—I was given a used computer, but there was no way I could enter the CMOS to make changes). It's important to note here that the password we are talking about is only the one that prevents a user from entering the BIOS setup at bootup, not the one that stops you from getting past the boot.

Normally, at bootup you can press a key (usually the DEL key) to access your BIOS allowing you to view it or make changes. With a password set, there is no way to enter setup. Though a password can provide a basic and very effective level of PC security, losing it can be a real headache if you don't know how to fix the problem.

The MS-DOS command that will makes this trick possible is the DEBUG command (debug itself is a utility—debug.exe—which is located in your Windows Command folder). This is not a command to be taken lightly—in other words, it's not a command to play with! You can cause serious corruption with this command and can end up not being able to even boot your computer! Debug is used to work with binary and executable files and allows you to alter (hex edit) the contents of a file or CPU register right down to the binary and byte level.

To begin debug mode, type debug at a MS-DOS prompt or you can specify a file, i.e., DEBUG FILE.EXE. There is a difference in screen output between the two methods. When you type DEBUG alone, debug responds with a hyphen (-) prompt waiting for you to enter commands. The second method, with a file specified, loads the file into memory and you type all the commands on the line used to start debug. In this tip, we will be writing to the BIOS, so the first method is the one that would be used. All debug commands can be aborted at any time by pressing CTRL/C.

Accessing BIOS with DEBUG
The basic trick will be to fool the BIOS into thinking there is a checksum error, in which case it resets itself, including the password. This is done by invalidating the CMOS and to do that we must know how to access the BIOS and where the checksum value of the CMOS is located so that we can change it. Access to the the BIOS content is via what are known as CMOS Ports and it's Port 70 and 71 that will give us the needed access. On almost all AT motherboards, the checksum is located at hexadecimal address 2e and 2f and filling the address 2e with ff is all you should have to do to invalidate the checksum.

Here's what to do if you ever need to reset the password and have no other method, and you don't want to open up your computer to remove the battery or jumpers.

Note! Do this at your own risk. I can only tell you that it has worked for me more than once and has worked for others as well. But I cannot make any guarantees. When I did this, I took a willing risk. The BIOS was Award Modular BIOS v4.51PG

Restart your computer in MS-DOS mode.


When you get to the C:\> or C:\WINDOWS> prompt, type DEBUG and press Enter.


A hyphen (-) prompt will appear waiting for you to enter commands.


Enter the following commands, pressing Enter after each one. Note: the o is the letter o and stands for OUTPUT.


o 70 2e


o 71 ff


q


After the q command (which stands for QUIT), enter Exit.


Then try to enter your BIOS at bootup. The password prompt should now be gone and you should now have full access to it again. However, you will now be at the default BIOS setttings and may want to change them to your preference. You may also want to have your drives autodetected again.
In closing, I should state that in the case of a lost BIOS password, your first step should always be to contact your manufacturer to see if a backdoor password is available that will allow you to bypass the forgotten password.

There are many sites on the net that list backdoor passwords you can try, but beware that some BIOS that are set up to lock up if you enter the wrong password more than a certain number of times, usually only 3 times!

If an essential Windows file gets whacked by a virus or otherwise corrupted, restore it from the Windows CD. Search the CD for the filename, replacing the last character with an underscore; for example, Notepad.ex_. If it's found, open a command prompt and enter the command EXPAND, followed by the full pathname of the file and of the desired destination: EXPAND D:\SETUP\NOTEPAD.EX_ C:\Windows\NOTEPAD.EXE. If either pathname contains any spaces, surround it with double quotes.

If the file isn't found, search on the unmodified filename. It will probably be inside a CAB file, which Win XP treats as a folder. Simply right-drag and copy the file to the desired location. In other Windows platforms, search for a file matching *.cab that contains the filename. When the search is done, open a command prompt and enter EXTRACT /L followed by the desired location, the full pathname of the CAB file, and the desired filename; for example: EXTRACT /L C:\Windows D:\I386\Driver.cab Notepad.exe. Again, if the destination or CAB file pathname contains spaces, surround it with double quotes.

"Take good care of your PC, and it will take good care of you."

It's a nice sentiment, but reality is more like "Take good care of your PC, and it won't crash, lose your data, and cost you your job--probably." Follow these steps to stop PC problems before they stop you.

Your PC's two mortal enemies are heat and moisture. Excess heat accelerates the deterioration of the delicate circuits in your system. The most common causes of overheating are dust and dirt: Clogged vents and CPU cooling fans can keep heat-dissipating air from moving through the case, and even a thin coating of dust or dirt can raise the temperature of your machine's components.

Any grime, but especially the residue of cigarette smoke, can corrode exposed metal contacts. That's why it pays to keep your system clean, inside and out.

If your PC resides in a relatively clean, climate-controlled environment, an annual cleaning should be sufficient. But in most real-world locations, such as dusty offices or shop floors, your system may need a cleaning every few months.

All you need are lint-free wipes, a can of compressed air, a few drops of a mild cleaning solution such as Formula 409 or Simple Green in a bowl of water, and an antistatic wrist strap to protect your system when you clean inside the case.

Think Outside the Box

Before you get started cleaning, check around your PC for anything nearby that could raise its temperature (such as a heating duct or sunshine coming through a window). Also clear away anything that might fall on it or make it dirty, such as a bookcase or houseplants.

Always turn off and unplug the system before you clean any of its components. Never apply any liquid directly to a component. Spray or pour the liquid on a lint-free cloth, and wipe the PC with the cloth.

Clean the case: Wipe the case and clear its ventilation ports of any obstructions. Compressed air is great for this, but don't blow dust into the PC or its optical and floppy drives. Keep all cables firmly attached to their connectors on the case.

Maintain your mechanical mouse: When a nonoptical mouse gets dirty, the pointer moves erratically. Unscrew the ring on the bottom of the unit and remove the ball. Then scrape the accumulated gunk off the two plastic rollers that are set 90 degrees apart inside the ball's housing.

Keep a neat keyboard: Turn the keyboard upside down and shake it to clear the crumbs from between the keys. If that doesn't suffice, blast it (briefly) with compressed air. If your keys stick or your keyboard is really dirty, pry the keys off for easier cleaning. Computer shops have special tools for removing keys, but you can also pop them off by using two pencils with broken tips as jumbo tweezers--just be sure to use a soft touch.

Make your monitor sparkle: Wipe the monitor case and clear its vents of obstructions, without pushing dust into the unit. Clean the screen with a standard glass cleaner and a lint-free cloth. If your monitor has a degauss button (look for a small magnet icon), push it to clear magnetic interference. Many LCDs can be cleaned with isopropyl alcohol; check with your LCD manufacturer. Wipe your LCD lightly: The underlying glass is fragile.

Check your power protection: Reseat the cables plugged into your surge protector. Check the unit's warning indicator, if it has one. Surge protectors may power your PC even after being compromised by a voltage spike (making your system susceptible to a second spike). If your power protector doesn't have a warning indicator and your area suffers frequent power outages, replace it with one that has such an indicator and is UL 1449 certified.

Swipe your CD and DVD media: Gently wipe each disc with a moistened, soft cloth. Use a motion that starts at the center of the disc and then moves outward toward the edge. Never wipe a disc in a circular motion.

Inside the Box

Before cracking open the case, turn off the power and unplug your PC. Ground yourself before you touch anything inside to avoid destroying your circuitry with a static charge. If you don't have a grounding wrist strap, you can ground yourself by touching any of various household objects, such as a water pipe, a lamp, or another grounded electrical device. Be sure to unplug the power cord before you open the case.

Use antistatic wipes to remove dust from inside the case. Avoid touching any circuit-board surfaces. Pay close attention to the power-supply fan, as well as to the case and to CPU fans, if you have them. Spray these components with a blast of compressed air to loosen dust; but to remove the dust rather than rearrange it, you should use a small vacuum.

If your PC is more than four years old, or if the expansion cards plugged into its motherboard are exceptionally dirty, remove each card, clean its contacts with isopropyl alcohol, and reseat it. If your system is less than a couple years old, however, just make sure each card is firmly seated by pressing gently downward on its top edge while not touching its face. Likewise, check your power connectors, EIDE connectors, and other internal cables for a snug fit.

While you have the case open, familiarize yourself with the CMOS battery on the motherboard. For its location, check the motherboard manual. If your PC is more than four or five years old, the CMOS battery may need to be replaced. (A system clock that loses time is one indicator of a dying CMOS battery.)

Look for Trouble

Give your PC a periodic checkup with a good hardware diagnostic utility. Two excellent choices are Sandra Standard from SiSoftware and #1-TuffTest-Lite from #1-PC Diagnostics. Download the free version of Sandra (the full version of the application costs $35) or to download #1-TuffTest-Lite (the fully functional version is $10).

Sandra Standard:
CODE
http://www.pcworld.com/downloads/file_description/0,fid,4005,tk,ur,00.asp


#1-TuffTest-Lite:
CODE
http://www.pcworld.com/downloads/file_description/0,fid,7725,tk,ur,00.asp


Adding and removing system components leaves orphaned entries in the Windows Registry. This can increase the time your PC takes to boot and can slow system performance. Many shareware utilities are designed to clean the Registry.

Windows stores files on a hard drive in rows of contiguous segments, but over time the disk fills and segments become scattered, so they take longer to access. To keep your drive shipshape, run Windows' Disk Defragmenter utility. Click Start, Programs (All Programs in XP), Accessories, System Tools, Disk Defragmenter. If your drive is heavily fragmented, you could boost performance. Defragging may take hours, however. Disable your screen saver and other automatic programs beforehand to keep the defrag from restarting every few minutes.

Disk Defragmenter won't defragment the file on your hard drive that holds overflow data from system memory (also known as the swap file). Since the swap file is frequently accessed, defragmenting it can give your PC more pep. You can defragment your swap file by using a utility such as the SpeedDisk program included with Norton SystemWorks 2004, but there's a way to reset it in Windows.

In Windows XP, right-click My Computer and choose Properties. Click Advanced, and then choose the Settings button under Performance. Click Advanced again and the Change button under Virtual Memory. Select another drive or partition, set your swap file size, and click OK.

If you have only one partition and no way to create a second one, and you have at least 256MB of RAM, disable the swap file rather than moving it: Select "No paging file" in the Virtual Memory settings. If you have trouble booting, start Windows in Safe Mode and re-enable this option.

Hard-Drive Checkup
Windows XP offers a rudimentary evaluation of your hard disk's health with its error-checking utility: Right-click the drive's icon in Windows Explorer and select Properties, Tools, Check Now. (Windows can fix errors and recover bad sectors automatically if you wish.) If the check discovers a few file errors, don't worry, but if it comes up with hundreds of errors, the drive could be in trouble.

To conduct a more thorough examination, download Panterasoft's free HDD Health utility, which monitors hard-drive performance and warns of impending disaster:
CODE
http://www.pcworld.com/downloads/file_description/0,fid,22945,tk,ur,00.asp


The program works only with drives that support S.M.A.R.T technology, but nearly all drives released since 2000 are S.M.A.R.T.-compliant.

Many hardware and software designers humbly assume you want their program running on your PC all the time, so they tell Windows to load the application at startup (hence, the ever-growing string of icons in your system tray). These programs eat up system resources and make hardware conflicts and compatibility problems more likely. To prevent them from launching, just click Start, Run, type "msconfig" and press Enter. The programs listed under the Startup tab are set to start along with Windows. Uncheck the box at the left of each undesirable program to prevent it from starting automatically.

Four Tips for Longer PC Life

1. Keep your PC in a smoke-free environment. Tobacco smoke can damage delicate contacts and circuits.

2. Leave your PC running. Powering up from a cold state is one of the most stressful things you can do to your system's components. If you don't want to leave your PC running all the time, use Windows' Power Management settings to put your machine into hibernation rather than completely shutting down. In Windows XP, right-click the desktop and select Properties. Click the Screen Saver tab and select the Power button. Choose the Hibernate tab to ensure that hibernation is enabled, and then select a time beneath "System hibernates" under the Power Schemes tab. (Note that this option is not available on all PCs.) Computers running older versions of Windows may or may not provide similar power-management features. Look under the Power Management icon (Power Options in Windows 2000) in Control Panel to evaluate your machine's capabilities.

3. Don't leave your monitor running. The best way to extend your display's life is to shut it off when it's not in use.

4. Avoid jostling the PC. Whenever you move your system, even if it's just across the desktop, make sure the machine is shut down and unplugged.

Partitioning your HardDisk

Partitioning involves creating logical units on your hard drive that are then addressed as different drive letters. Not only does it help to organize your data (program files on one drive, games on another, documents on another) but also to speed up your PC. This is so because the drive head has to move a lesser distance for accessing data within one partition. You can also have different filesystems and OSs on the same hard drive.

Partitioning can be done using ‘fdisk’ in DOS/Windows 9x or ‘disk management’ in Windows 2000/ NT/XP. We will describe the procedure for fdisk, since disk management is GUI driven and the basics otherwise remain the same. While several other commercial packages like Partition Magic are available, these utilities (fdisk, computer management) are bundled with their respective OSs. You need a bootable floppy with fdisk.exe, format.com, and sys. com utilities. Before starting, decide how many partitions you want to create and their sizes. You can create one primary and one extended partition using the DOS fdisk. The extended partition can then have multiple logical partitions. Boot your machine using the bootable disk, and do the following.

Run fdisk. The utility will show you a numbered menu from where you can create, view, or delete partitions
The utility first asks you whether you want to enable large disk support. Type Y (for yes) and press enter if your hard-drive capacity is more than 4 GB. Large disk support creates a FAT32 partition, which can be greater than 2 GB
Select the first option from fdisk menu to create a primary partition. Specify the partition size in megabytes or percentage size when prompted for it
Similarly, create an extended partition. Extended partitions by themselves do not appear as drive letters. Instead, logical partitions must be created in them, which are then assigned drive letters
Exit fdisk and reboot the computer
Fdisk automatically assigns drive letters to all the partitions. You’ll need to format each partition in order to use it. Use format.com for the same
Your hard drive is now ready for taking an OS.

Beep Code Manual, Better Than Gold Techies, American Megatrends Int. & Phoenix

(I'm IT, I use these codes to trouble shoot hardware issues at my job. Enjoy) cold.gif

BIOS Beep Codes

When a computer is first turned on, or rebooted, its BIOS performs a power-on self test (POST) to test the system's hardware, checking to make sure that all of the system's hardware components are working properly. Under normal circumstances, the POST will display an error message; however, if the BIOS detects an error before it can access the video card, or if there is a problem with the video card, it will produce a series of beeps, and the pattern of the beeps indicates what kind of problem the BIOS has detected.
Because there are many brands of BIOS, there are no standard beep codes for every BIOS.

The two most-used brands are AMI (American Megatrends International) and Phoenix.

Below are listed the beep codes for AMI systems, and here are the beep codes for Phoenix systems.


AMI Beep Codes

Beep Code Meaning
1 beep DRAM refresh failure. There is a problem in the system memory or the motherboard.
2 beeps Memory parity error. The parity circuit is not working properly.
3 beeps Base 64K RAM failure. There is a problem with the first 64K of system memory.
4 beeps System timer not operational. There is problem with the timer(s) that control functions on the motherboard.
5 beeps Processor failure. The system CPU has failed.
6 beeps Gate A20/keyboard controller failure. The keyboard IC controller has failed, preventing gate A20 from switching the processor to protect mode.
7 beeps Virtual mode exception error.
8 beeps Video memory error. The BIOS cannot write to the frame buffer memory on the video card.
9 beeps ROM checksum error. The BIOS ROM chip on the motherboard is likely faulty.
10 beeps CMOS checksum error. Something on the motherboard is causing an error when trying to interact with the CMOS.
11 beeps Bad cache memory. An error in the level 2 cache memory.
1 long beep, 2 short Failure in the video system.
1 long beep, 3 short A failure has been detected in memory above 64K.
1 long beep, 8 short Display test failure.
Continuous beeping A problem with the memory or video.
BIOS Beep Codes


Phoenix Beep Codes

Phoenix uses sequences of beeps to indicate problems. The "-" between each number below indicates a pause between each beep sequence. For example, 1-2-3 indicates one beep, followed by a pause and two beeps, followed by a pause and three beeps. Phoenix version before 4.x use 3-beep codes, while Phoenix versions starting with 4.x use 4-beep codes. Click here for AMI BIOS beep codes.
4-Beep Codes
Beep Code Meaning
1-1-1-3 Faulty CPU/motherboard. Verify real mode.
1-1-2-1 Faulty CPU/motherboard.
1-1-2-3 Faulty motherboard or one of its components.
1-1-3-1 Faulty motherboard or one of its components. Initialize chipset registers with initial POST values.
1-1-3-2 Faulty motherboard or one of its components.
1-1-3-3 Faulty motherboard or one of its components. Initialize CPU registers.
1-1-3-2
1-1-3-3
1-1-3-4 Failure in the first 64K of memory.
1-1-4-1 Level 2 cache error.
1-1-4-3 I/O port error.
1-2-1-1 Power management error.
1-2-1-2
1-2-1-3 Faulty motherboard or one of its components.
1-2-2-1 Keyboard controller failure.
1-2-2-3 BIOS ROM error.
1-2-3-1 System timer error.
1-2-3-3 DMA error.
1-2-4-1 IRQ controller error.
1-3-1-1 DRAM refresh error.
1-3-1-3 A20 gate failure.
1-3-2-1 Faulty motherboard or one of its components.
1-3-3-1 Extended memory error.
1-3-3-3
1-3-4-1
1-3-4-3 Error in first 1MB of system memory.
1-4-1-3
1-4-2-4 CPU error.
1-4-3-1
2-1-4-1 BIOS ROM shadow error.
1-4-3-2
1-4-3-3 Level 2 cache error.
1-4-4-1
1-4-4-2
2-1-1-1 Faulty motherboard or one of its components.
2-1-1-3
2-1-2-1 IRQ failure.
2-1-2-3 BIOS ROM error.
2-1-2-4
2-1-3-2 I/O port failure.
2-1-3-1
2-1-3-3 Video system failure.
2-1-1-3
2-1-2-1 IRQ failure.
2-1-2-3 BIOS ROM error.
2-1-2-4 I/O port failure.
2-1-4-3
2-2-1-1 Video card failure.
2-2-1-3
2-2-2-1
2-2-2-3 Keyboard controller failure.
2-2-3-1 IRQ error.
2-2-4-1 Error in first 1MB of system memory.
2-3-1-1
2-3-3-3 Extended memory failure.
2-3-2-1 Faulty motherboard or one of its components.
2-3-2-3
2-3-3-1 Level 2 cache error.
2-3-4-1
2-3-4-3 Motherboard or video card failure.
2-3-4-1
2-3-4-3
2-4-1-1 Motherboard or video card failure.
2-4-1-3 Faulty motherboard or one of its components.
2-4-2-1 RTC error.
2-4-2-3 Keyboard controller error.
2-4-4-1 IRQ error.
3-1-1-1
3-1-1-3
3-1-2-1
3-1-2-3 I/O port error.
3-1-3-1
3-1-3-3 Faulty motherboard or one of its components.
3-1-4-1
3-2-1-1
3-2-1-2 Floppy drive or hard drive failure.
3-2-1-3 Faulty motherboard or one of its components.
3-2-2-1 Keyboard controller error.
3-2-2-3
3-2-3-1
3-2-4-1 Faulty motherboard or one of its components.
3-2-4-3 IRQ error.
3-3-1-1 RTC error.
3-3-1-3 Key lock error.
3-3-3-3 Faulty motherboard or one of its components.
3-3-3-3
3-3-4-1
3-3-4-3
3-4-1-1
3-4-1-3
3-4-2-1
3-4-2-3
3-4-3-1
3-4-4-1
3-4-4-4 Faulty motherboard or one of its components.
4-1-1-1 Floppy drive or hard drive failure.
4-2-1-1
4-2-1-3
4-2-2-1 IRQ failure.
4-2-2-3
4-2-3-1
4-2-3-3
4-2-4-1 Faulty motherboard or one of its components.
4-2-4-3 Keyboard controller error.
4-3-1-3
4-3-1-4
4-3-2-1
4-3-2-2
4-3-3-1
4-3-4-1
4-3-4-3 Faulty motherboard or one of its components.
4-3-3-2
4-3-3-4 IRQ failure.
4-3-3-3
4-3-4-2 Floppy drive or hard drive failure.
3-Beep Codes
Beep Code Meaning
1-1-2 Faulty CPU/motherboard.
1-1-3 Faulty motherboard/CMOS read-write failure.
1-1-4 Faulty BIOS/BIOS ROM checksum error.
1-2-1 System timer not operational. There is a problem with the timer(s) that control functions on the motherboard.
1-2-2
1-2-3 Faulty motherboard/DMA failure.
1-3-1 Memory refresh failure.
1-3-2
1-3-3
1-3-4 Failure in the first 64K of memory.
1-4-1 Address line failure.
1-4-2 Parity RAM failure.
1-4-3 Timer failure.
1-4-4 NMI port failure.
2-_-_ Any combination of beeps after 2 indicates a failure in the first 64K of memory.
3-1-1 Master DMA failure.
3-1-2 Slave DMA failure.
3-1-3
3-1-4 Interrupt controller failure.
3-2-4 Keyboard controller failure.
3-3-1
3-3-2 CMOS error.
3-3-4 Video card failure.
3-4-1 Video card failure.
4-2-1 Timer failure.
4-2-2 CMOS shutdown failure.
4-2-3 Gate A20 failure.
4-2-4 Unexpected interrupt in protected mode.
4-3-1 RAM test failure.
4-3-3 Timer failure.
4-3-4 Time of day clock failure.
4-4-1 Serial port failure.
4-4-2 Parallel port failure.
4-4-3 Math coprocessor.