When a computer is powered up (turned on) a diagnostic routine is completed befire the computer gives way to software control. The hardware diagnostic routine is called Power On Self Test (POST). Errors or faults with hardware may be found during POST and these are reported to the user.

Non Fatal errors are those that, in most cases, allow the system to continue the boot up process. Non fatal error messages normally appear on the screen.

Fatal Errors are those will not allow the system to continue the buut up procedure. Fatal Errors are usually communicated to the user through a series of audible beeps. The are may long beep followed by a number of short beep and the sequence is repeated. Some BIOS routines will vary from thise shown below and some do not use the initial long beep.

Those listed below are usually fatal errors:

Note: these beeps follow the LONG initial Beep..


One Beep --- Refresh Failure --- The memory refresh circuitry of the motherboard is faulty.

Two Beeps --- Parity Error --- A parity error was detected in the base memory.

Three Beeps --- Base 64 Kb memory failure --- Memory failure within the first 64Kb of memory.

Four Beeps --- Timer not operational --- The main timer on the mother board has failed to function.

Five Beeps --- Processor error --- The CPU has generated an error.

Six Beeps --- Gate A20 failure --- This error message means that the ROM BIOS is not able to switch the CPU into Protect Mode. This is not always a fatal error.

Seven Beeps --- CPU exception interrupt error --- This is caused by a hardware conflict when two items of hardware are trying to use thesame IRQ.
(go to this thread for more info on Hardware conflict: http://www.antionline.com/showthread...hreadid=155337 )

Eight Beeps --- Screen Controller --- Display error. The screen controller is missing, not plugged in the mother board correctly or its memory is faulty.

Nine Beeps --- ROM checksum --- The ROM checksum value does not match the value encoded in the ROM BIOS.

Ten Beeps --- CMOS shutdown register --- The shutdown register for CMOS memory read/write has failed.


I hope this tutorial is useful for you...