Most of you have heard a single short beep sound when your computer starts. May be you never heard about purpose of this beep but this beep is so common to us that without knowing about it, yet we understands that single short beep means that computer is turned on properly. Not a big deal, even if something happens, they call their tech guys and they solve them for it. But some of want to look inside that mighty computer's cabinet.
In simple words, whenever computer starts, it goes for a TEST that is known as POST (Power-On Self Test), under that it also follows instructions from BIOS (Basic Input / Output System) which do various tests for on computer and if there is any problem then it reports to us via various combination of BEEPs through the system speaker (one which is found inside the PC). Bios is basically comes with your motherboard and you do not have to worry about it much. It is installed on EPROM (Erasable Programmable read Only Memory) and you can even update it but thats risky most of the time, do it when you know it.
Don't worry, you do not have to remember all the text I wrote above, just remember When computer boots, it makes various combination of beeps which may tell us the source or reason of problem (if there is any). .
For example, recently one of my old computer (which I tried to restore) just started making long continues beeps when I tried to turn on after many years. I understood that is RAM went wrong. I tested RAM in another computer and confirmed that my RAM went bad, I brought new RAM and its now running.
So, from the pattern of beeps, you can figure what problem your computer have. But, there are many BIOS manufacturer and they all have different sets of beep, however here I am trying to provide as much info I can find.
If you have AMI BIOS
1 beep Refresh failure
2 beeps Parity error
3 beeps Base 64K memory failure
4 beeps Timer not operational
5 beeps Processor error
6 beeps 8042 - gate A20 failure
7 beeps Processor exception interrupt error
8 beeps Display memory read/write failure
9 beeps ROM checksum error
10 beeps CMOS shutdown register read/write error
11 beeps Cache memory bad
If your system is with AWARD BIOS
1 short: System boots successfully
2 short: CMOS setting error
1 long 1 short: DRAM or M/B error
1 long 2 short: Monitor or display card error
1 long 3 short: Keyboard error
1 long 9 short: BIOS ROM error
Continuous long beeps: DRAM error
Continuous short beeps: Power error
If Your System is with Phoneix BIOS
(Here 1-1-3 means 1 beep then a pause then 1 beep and a pause and then 3 continues beeps)
1-1-3 Your computer can't read the configuration info stored in the CMOS.
1-1-4 Your BIOS needs to be replaced.
1-2-1 You have a bad timer chip on the motherboard.
1-2-2 The motherboard is bad.
1-2-3 The motherboard is bad.
1-3-1 You'll need to replace the motherboard.
1-3-3 You'll need to replace the motherboard.
1-3-4 The motherboard is bad.
1-4-1 The motherboard is bad.
1-4-2 Some of your memory is bad.
2-_-_ Any combo of beeps after two means that some memory is bad.
3-1-_ One of the chips on your motherboard is broken.
3-2-4 One of the chips on your motherboard that checks the keyboard is broken.
3-3-4 Your computer can't find the video card.
3-4-_ Your video card isn't working. You'll need to replace it.
4-2-1 There's a bad chip on the motherboard. You need to buy another board.
4-2-2 First check the keyboard for problems. If nothing, you have a bad motherboard.
4-2-3 Same as 4-2-2.
4-2-4 One of the cards is bad.
4-3-1 Replace the motherboard.
4-3-2 See 4-3-1
4-3-3 See 4-3-1
4-3-4 Time of day clock failure.
4-4-1 Serial port problem
4-4-2 Parallel port resource problem
4-4-3 Math coprocessor is having problems.
Low 1-1-2 Motherboard is having problems
Low 1-1-3 This is an Extended CMOS RAM problem, check your motherboard battery, and motherboard.