Common BIOS Problems
Many USB Problems are the result of improper settings in the BIOS. To achieve proper USB connectivity the BIOS needs to be a properly working partner.
Enable USB in the BIOS
USB is often disabled by Default in the BIOS. To enable USB in the BIOS one or more of the following statements must be true.
USB Keyboard - DOS or Enabled (Even if you have NO USB Keyboard)
Legacy USB Support - Enabled
Assign IRQ for USB - Enabled (Some combinations of OS and BIOS version require this setting to be Disabled).
BIOS settings Effecting USB
BIOS settings that effect the operation of Universal Serial Bus are shown optimized for USB. The most common BIOS settings that effect USB performance are:
Reset the FSB to Default
Aggressive memory settings (Turbo/Fast)
Reset to Normal or Default
Lack of usable IRQs
Com1 and Com2 can be disabled if not used, allowing the OS to use these IRQs for other devices.
Plug and Play OS – Disabled
* Older Win9x (Socket 7 based) systems may require this option to be Enabled to allow Windows controlled IRQ Steering to operate correctly. Toggle ON or OFF as your system requires.
IRQs Assigned – Auto
Power Management – Disabled
* The Operating System should control Power Management.
ACPI - Disabled
* ACPI enabled in the BIOS is the source of many USB problems. If you are having problems with USB, ACPI should be disabled. Unfortunately, simply resetting the switch in the BIOS may not be enough. Normally, a reinstall of the operating system will be necessary. Remember to backup your data before you reinstall the OS. I recommend a clean install to a newly formatted hard drive.
o Clean Install Guide
o Win2000 Common Problems
USB Keyboard – Enabled or DOS
Assign IRQ for USB – This setting varies by motherboard type. The “rule of thumb” is, Enabled for Win2000 and Disabled for Win9X. Try both settings if you are having problems