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Other BIOS Troubleshooting Tips

Use Table 3.6 to help solve some other typical system problems through BIOS configuration settings.

Table 3.6 Troubleshooting Common BIOS-Related System Problems




Can't access system because passwords for startup or setup access aren't known.

Passwords are stored in CMOS non-volatile RAM (NVRAM) and are configured through BIOS.

Remove battery on motherboard and wait for all CMOS settings to be lost or use MB jumper called "clear CMOS"; before clearing CMOS, view bootup configuration information and note hard drive and other configuration information, because all setup information must be re-entered after CMOS is cleared.

System wastes time detecting hard drives at every bootup.

Disable automatic drive detection in BIOS; "lock in" settings for drives by using "detect drives" option in BIOS.


System drops network or modem connection when system is idle.

Power management not set correctly for IRQs in use by modem or network card.

Determine which IRQs are used by devices and adjust power management for those devices; disable power management in BIOS.

Parallel or serial port conflicts.

Change configuration in BIOS.

See Chapters 6 and 7 for details.

For more about troubleshooting and adjusting BIOS configuration settings, see Chapter 5 of Upgrading and Repairing PCs, 12th Edition, published by Que.

Soft BIOS CPU Speed and Multiplier Settings

Conventional motherboards might require the user to configure CPU speed, FSB (motherboard or system bus) speed, and clock multipliers through a series of jumpers or switches or through BIOS configuration screens. One danger to BIOS configuration is that the user might create a configuration that won't allow the system to boot, and might require the CMOS configuration to be deleted to enable the user to try another option.

As an alternative, ABIT motherboards have pioneered BIOS- controlled configuration of CPU speeds, clock multipliers, FSB (motherboard/system bus) speeds, and other options using a feature called SoftMenu III that also enables hardware overrides.

SoftMenu III enables users to do the following:

  • Adjust FSB speeds up to 200MHz

  • Adjust core voltage

  • Adjust AGP and PCI clock ratios

If the user creates an "impossible" combination of settings that won't permit the system to boot, a set of DIP switches on motherboards using SoftMenu III can override the BIOS configuration, enabling the system to boot.

Determining Which BIOS You Have

It's important to know which BIOS brand and version a computer has for two reasons.

First, in the event of a boot failure, BIOS error codes, which vary by brand and model, can be used to help you find the cause of the problem and lead you to a solution.

Second, knowing which BIOS brand and version you have can enable you to get help from the BIOS or system vendor for certain chipset configuration issues.

To determine which BIOS you have, use the following methods:

  • Watch your system startup screen for information about the BIOS brand and version, such as "Award BIOS v4.51PG."

  • Use a hardware test-and-reporting utility, such as Microsoft's venerable MSD.EXE, AMIDiag, CheckIt, or others.

Note that the best source for machine-specific information about error codes and other BIOS issues is your system manufacturer. Major vendors, such as IBM, Dell, Compaq, Gateway, Hewlett-Packard, and others, maintain excellent Web sites that list specific information for your system. However, if you are working with a white-box clone system made from generic components, BIOS-level information might be the best information you can get.

Determining the Motherboard Manufacturer for BIOS Upgrades

While knowing the BIOS brand and version is sufficient for troubleshooting a system that won't start, solving problems with issues such as year-2000 compliance, large hard disk support, and power management requires knowing exactly which motherboard you have and who produced it. Because motherboard manufacturers tailor BIOS code to the needs of each motherboard model, the motherboard or system vendor—not the BIOS vendor—is the source to turn to for BIOS upgrades and other BIOS configuration issues.

Identifying Motherboards with AMI BIOS

Motherboards using AMI BIOS versions built from 1991 to the present (AMI's High-Flex BIOS or WinBIOS) display a long string of numbers at the bottom of the first screen that is displayed when the system is powered on or restarted:


Interpret a number such as this one with the following numerical key (see Table 3.7):






Processor Type:


0 = 8086 or 8088


2 = 286


3 = 386


4 = 486


5 = Pentium


6 = Pentium Pro/II


Size of BIOS:


0 = 64KB BIOS


1 = 128KB BIOS


Major and minor BIOS version number


Manufacturer license code reference number:


0036xx = AMI 386 motherboard, xx = Series #


0046xx = AMI 486 motherboard, xx = Series #


0056xx = AMI Pentium motherboard, xx = Series #


0066xx = AMI Pentium Pro motherboard, xx = Series #


(for other numbers see the following note)


1 = Halt on POST Error


1 = Initialize CMOS every boot


1 = Block pins 22 and 23 of the keyboard controller


1 = Mouse support in BIOS/keyboard controller


1 = Wait for F1 key on POST errors


1 = Display floppy error during POST


1 = Display video error during POST


1 = Display keyboard error during POST


BIOS Date, mm/dd/yy


Chipset identifier or BIOS name


Keyboard controller version number


Use the following resources to determine the manufacturer of non-AMI motherboards using the AMI BIOS:

AMI has a listing of U.S. and non-U.S. motherboard manufacturers at the following address:


AMI also offers a downloadable utility program called AMIMBID for use with Windows 9x/2000/NT and MS-DOS. Follow the AMI Motherboard Identification Utility link from the AMI Technical Support page, available as a link from the following address:


A more detailed listing, including complete identification of particular motherboard models, is available at Wim's BIOS page (http://www.ping.be/bios/). This site also has links to motherboard manufacturers for BIOS upgrades.

Identifying Motherboards with Award BIOS

Motherboards with the Award Software BIOS also use a numerical code, although the structure is different from that for the AMI Hi-Flex BIOS.

The following is a typical Award BIOS ID:


The sixth and seventh characters (bolded for emphasis) indicate the motherboard manufacturer, whereas the eighth character can be used for the model number or the motherboard family (various motherboards using the same chipset).


For lookup tables of these codes, see the following Web sites:

Award Software's official table for manufacturers only is available at http://www.phoenix.com/pcuser/BIOS/motherboard.htm.

An expanded list, also containing chipset information (stored in the first five characters of the Award BIOS ID), is available at Wim's BIOS site (http://www.ping.be/bios/).

Identifying Motherboards with Phoenix or Microid Research BIOS

Unfortunately, neither Phoenix nor Microid Research (MR BIOS) use any type of a standardized motherboard ID number system.

For systems using a Phoenix BIOS, see whether your motherboard or system is listed on the Micro Firmware BIOS upgrades page. Links from this page for Intel and Micronics motherboards list the codes that show up onscreen during boot. Match these codes to your system and you might be able to use a Micro Firmware upgrade. Most MR BIOS (Microid Research BIOS) installations are done as upgrades rather than in original equipment. See the list of supported chipsets (identified by chipset brand and model, not motherboard vendor) and motherboards using Intel's Triton-series chipsets to see whether your system can use an MR BIOS, or contact Microid Research directly for system-specific information.

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