BIOS ( Basic Input and Output System ) -  Error Codes/Beeps -  Entering BIOS/CMOS

Software stored in a Read-Only Memory (ROM) chip on the motherboard (CMOS).  It controls systems devices and test memory. It allows you to configure specific parameters about the hardware in your computer such as time, date, hard drive parameters and other device settings.

Beeps are emitted from a computer during the boot process when some problem is encountered and can be used to troubleshoot a dead computer.  They indicate problems such as bad memory, bad keyboard or bad motherboard.  Usually if you hear beeps there is something real wrong and you should immediately turn off the computer and perform some troubleshooting. 

POST Beeping Error General Codes

• Bad Motherboard - 1 long and 1 short beep
• Disk drive related problem / Video card problem - 1 short beep then nothing happens
• Bad video card - 1 long and 2 short beeps
• Bad power supply - 1) continuous beeps, 2) non-stop short beeps
• Bad memory - 3 short beeps

These codes DO vary from one manufacturer to another.  Almost all computers list the appropriate codes in the User's manual under technical information or the troubleshooting section, so be sure to check the manual and verify what the codes mean.

If no beeps are heard and no display is on the screen, its most likely the power supply.  Check for Keyboard lights or for hard drive/floppy drive lights.  If lights come on then power supply is good.

Next, inspect the motherboard for loose components. A loose or missing CPU, BIOS chip, Crystal Oscillator, or Chipset chip will cause the motherboard not to function.  If you get lights then it could be one of the I/O cards.  Try removing each card one at a time and restarting the computer.

Error Codes/Beeps for AMI, Award, Compaq, IBM, Phoenix, BIOS's

AMI

AMI Beep Codes

Except for beep code #8, these codes are always fatal.

1 beep Refresh failure
   - try reseating the memory, if the error still occurs, replace the memory
2 beeps Parity error
    - try reseating the memory, if the error still occurs, replace the memory
3 beeps Base 64K memory failure
   - try reseating the memory, if the error still occurs, replace the memory
4 beeps Timer not operational, system board bad
5 beeps Processor error, system board bad
6 beeps 8042 - gate A20 failure, try reseating the keyboard controller chip
7 beeps Processor exception interrupt error, system board bad
8 beeps Display memory video card read/write failure error, replace video memory or video card
9 beeps ROM checksum error, faulty BIOS chip(s), must replace them
10 beeps CMOS shutdown register read/write error, system board bad
11 beeps Cache memory bad

Award

Award BIOS Beep codes

One Long and Two Short Beeps Video Error
Two Short Beeps Any Non-Fatal Error
One Short Beep No Error During Post

Phoenix 

Phoenix BIOS Beep codes

These codes are presented in sets of beeps, for instance 1-2-2-3 means one beep followed by 2 beeps then 2 more beeps then 3 beeps

• 1-2-2-3 BIOS ROM checksum
• 1-3-1-1 Test DRAM refresh
• 1-3-1-3 Test 8742 Keyboard Controller
• 1-3-4-1 RAM failure on address line xxxx
• 1-3-4-3 RAM failure on data bits xxx of low byte of memory
• 1-4-1-1 RAM failure on data bits xxxx of high byte of memory bus
• 2-1-2-3 Check ROM copyright notice
• 2-1-3-1 Test for unexpected interrupts
• 1-2 .......Search for option ROMs
• 1 ...........One short beep before boot, normal

You would enter the BIOS for the following reasons:

• To change the a hard drive designation
• To enable or disable com ports
• To change parameters of the com ports or parallel ports
• To change the power on password
• To allow the BIOS to change the amount of memory installed

You should only enter the BIOS immediately after booting the computer and never from within an operating system (i.e. Windows). On some computers you can enter the BIOS from a DOS prompt.

Several  ways can be used to enter the BIOS/CMOS:

The video monitor will usually say on the bottom of the screen just as the computer is turned on, which key to use.

The BIOS information is stored in the CMOS hardware section of the motherboard and the contents are maintained by applying constant electrical current using a CMOS battery.

to enter the BIOS during boot up hold down one of the following keys:

• Hold down the <Del> key
• Hold down the <F1> key
• Hold down the <F10> key

To enter the BIOS from a DOS prompt...( ...NOT from inside windows)

• <Alt><Cntrl><Esc>
• <Alt><Cntrl><Enter>
• <Cntrl> <Alt> <A>
• <Cntrl> <Alt> <S>

Some manufacturers have their own way for entering BIOS as shown below...

• Acer - Ctrl+Alt+Esc
• Compaq - F10
• Compaq Presario - Press <Alt> <Ctrl> <Esc> at boot when you see the "Compaq" log in big letters
• Dell - F1 or Del.
• Gateway 2000 - F1
• Hewlett Packard - F1
• IBM
  • Older Models - In order to get into the configuration of the IBM setup screen (CMOS) screen you need to hold down both mouse buttons during boot-up.
  • Aptiva - Press F1
• Leading Edge
  • Fortiva 5000 - <Cntrl> <Alt> <A> or <Cntrl> <Alt> <S>
• NEC - F2
• Packard Bell - F1 or F2
• Sharp Laptop 9020 - F2
• Sony - F3, then F2, or F1
• Tandon computers - Hold down the <Esc> key after turning on power
• Toshiba Laptops - Toshiba Utility