When a computer's power is turned on, it begins with a self test of the components and hardware attached. This test is called the POST test (for Power On Post Test). During the test the computer will spill any of the problems onto the screen in the form of a number or to the speaker in the form of beeps. The following tables are meant to help the user to find the code and problem related to the code.

This first table is comprised of those numeric error codes.

The message Usually means Comments
02X Power Supply You may need to replace your power supply.
1XX Motherboard These numbers often translate to expensive problems.
2XX Memory Try pushing your memory chips more firmly into their sockets. If that doesn't work, you probably need to have your chips tested.
3XX Keyboard Something may be holding a key down or maybe one is sticking. Another possible solution is to shut down, shake the dust from the keyboard, and restart.
4XX Monochrome Video Only XT's complain about this problem. The monochrome video card is acting up.
5xx Color Video Only XT's complain about this problem. The CGA video card is acting up.
6XX Floppy Drive or Adapter Could there be a bad floppy in the drive? Is the CMOS set up for the right type of disk? Check drive ascociations and the drive type.
7XX Math Coprocessor Is the math coprocessor seated firmly in its socket? Does the CMOS know that the coprocessor is attached? Check the settings.
9XX Printer Port Your I/O card may be at fault. See that it is seated properly.
10XX Second Printer Port Your I/O card may be at fault. See that it is seated properly.
11XX Serial Port Your I/O card may be at fault. See that it is seated properly.
12XX Second Serial Port Your I/O card may be at fault. See that it is seated properly.
13XX Game card Your I/O card may be at fault. See that it is seated properly.
17XX Hard Drive or Controller Make sure that the hard drive cables are securely fastened and polarized. Double check the jumper settings. Also make sure that the I/O card is seated firmly.

Error codes also come in the form of words. The following is a list of error messages in words:

Key words Meaning
64K Some of the memory has probably gone bad. Have the memory chips tested.
Bad DMA Your mother board may need replacing.
Bad or missing Command Interpereter Your computer isss looking for file called COMMAND.COM, which is supposed to be in its root directory. Copy that file back to the root directory. Ensure that the disk is formated for use with the system.
CMOS, Configuration When the computer mentions CMOS, you need to change some of its settings. Check all the settings for errors.
Drive Failure Ensure that the drive cables are connected firmly and that they are correctly polarized. Check power and polarization. Check the CMOS setting for the drive.
Memory and Failure When combined in the same message, these two words usually mean something's wrong with yuor memory chips. Your best bet is to have the memory chips tested. You may have to change motherboards.
Non-system disk or disk error Take out the disk that's in drive A and press the spacebar for a quick fix. If your computer sendss this about the hard drive, you need to copy COMMAND.COM to the hard drive from your System disk. Running format /s would also prepare the hard disk.
Parity Your memory is acting up. Try pressing the chips more firmly into the sockets or have the chips checked.
Partition table Your hard drive is acting up. Your best bet is to buy a hard drive installation utility and let the utility fix the error. Or, if experienced, run an f-disk on the drive to change to fat 32 or fat 16.
Sector not found or Unrecoverable error This means that the disk is starting to go bad. Programs such as Norton's Utilities or PC Tools can help to recover any information before it's too far gone to retrieve.
Timer Problems with timers usually mean that your computer's motherboard is defective.

Other messages are in the form of beeps. These can obviously be used if the pc speaker is connected. It will not come over the speaker through the sound card because the PC has not booted and is in POST test mode. There is a different table for different Bios versions. Check you Bios version and refer to the corresponding table.

Number of Beeps Meaning (AMI BIOS)
No beep You're supposed to hear one beep. If you don't hear anything, your computer is suffering from a bad power supply, bad motherboard, or a speaker that doesn't work.
1 beep Normally, computers issue a single self-assuring beep when everything is working fine. But when nothing apperas on the screen, you'd better check your monitor or video card. If both of these parts seem to be working fine, your computer is struggling with some bad chips. This is a job for professionals.
2 Beeps Your computer is complaining about its memory. Try pushing your memory chips more firmly into their sockets. If that doesn't work, you probably need to have your chips tested.
3 Beeps Same as the 2 Beeps messagee.
4 Beeps Nearly always same as the 2 Beeps message.
5 Beeps Your motherboard is acting up. Try reseating all the chips, especially the CPU. If that doesn't work, you may need to test the chips. If they test well, the motherboard may need replaced.
6 Beeps The keyboard controller chip on your motherboard is acting up or your keyboard needs replaced.
7 Beeps Your motherboard is acting up. Try reseating all the chips, especially the CPU. If that doesn't work, you may need to test the chips. If they test well, the motherboard may need replaced.
8 Beeps This is your video card acting up. You may need to check the jumpers, see that the embeded video is disabled, or check bios settings.
9 Beeps Your Bios is acting up and may need replaced.
10 Beeps Your mother board is acting up. If this problem persists, you may have to replace it.
11 Beeps Your mother boards cache memory has problems. Check that the chips are the same type and that the jumpers for the amount of memory is correct.
Type of Beeps Meaning (Genuine IBM Bios)
No Beep You're supposed to hear one beep. If you don't hear anything, your computer is suffering from a bad power supply, bad motherboard, or a speaker that doesn't work.
Constant Beep Your Power supply isn't working right.
Short/repetetive beeps Your Power supply isn't working right.
One Long Beep and one short one Your motherboard isn't working right.
One Long, Two Short Your video card or cables are not working right.
One Long, Three Short Your EGA card of its cables are not working right.
Type of Beep Series Meaning (Pheonix Bios)
1-1-3 Your computer can't read the CMOS.
1-1-4 Your Bios probably needs replaced.
1-2-1 Atimer chip on your mother board is acting up; you'll probably need to replace the mother board.
1-2-2 The motherboard is bad.
1-2-3 You have a bad motherboard or memory. Try reseating the memory chips.
1-3-1 You have a bad motherboard or memory. Try reseating the memory chips.
1-3-3 You have a bad motherboard or memory. Try reseating the memory chips.
1-3-4 You probably have a bad motherboard.
1-4-1 You probably have a bad motherboard.
1-4-2 Some of the memory is bad. Try reseating the memory chips.
2-X-X Any number begining with the two beeps means the memory is bad. Try to reseat the chips or have them tested.
3-1-1 One of the chips on your motherboard is acting up; you'll probably have to replace the whole thing.
3-1-2 One of the chips on your motherboard is acting up; you'll probably have to replace the whole thing.
3-1-3 One of the chips on your motherboard is acting up; you'll probably have to replace the whole thing.
3-1-4 One of the chips on your motherboard is acting up; you'll probably have to replace the whole thing.
3-2-4 Your keyboard or its controller chip is acting up.
3-3-4 The computer can't locate the video card.
3-4-1 The video card is acting up.
3-4-2 The video card is acting up.
3-4-3 The video card is acting up.
4-2-1 One of the chips on your motherboard is acting up; you'll probably have to replace the whole thing.
4-2-2 Check the keyboard and controller first, if that doesn't work, it is probably the motherboard.
4-2-3 Same as above.
4-2-4 One of your cards is confusing your computer. Try pulling cards, one at a time, to find the culprit.
4-3-1 The motherboard has probably gone bad.
4-3-2 The motherboard has probably gone bad.
4-3-3 One of the timer chips is acting up; you'll probably have to replace the whole thing.
4-3-4 Try calling up you CMOS and checking you date and time. If that doesn't fix the problem try a new battery. If the problem still persists, try a new power supply before buying a new motherboard.
4-4-1 Your serial port is acting up, try reseating or replacing your I/O card.
4-4-2 Your parallel port is acting up; try reseating or replacing your I/O card.
4-4-3 Your math coprocessor is acting up. Try reseating or replacing it. Run the program it came with to se if it is bad or just pretending.

For further troubleshooting idas, refer to my troubleshooting page. There is a list of other messages and their meanings on that page after POST test.

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