From HP's website http://h20000.www2.hp.com/bizs.....0405101#A1
Configuration settings for the computer, such as system passwords and BIOS values, are stored in CMOS memory. Occasionally, CMOS may be corrupted, usually due to improperly functioning software or hardware, or the addition or removal of expansion boards. If CMOS is corrupted, you can clear it and reset it to its original (factory) configuration. This resets the software settings that include the boot sequence order and other BIOS values. It will not, however, force hardware rediscovery.
NOTE: Resetting CMOS clears any current passwords and resets them to the factory defaults, which are null.
Resetting CMOS on the System Board
To reset CMOS using the CMOS reset switch:
* Power off the system.
* Disconnect and remove the AC power cord.
* Remove the access panel.
* Locate the CMOS reset switch on the system board.
* Depress the switch for 3 to 5 seconds.
* Replace the access panel.
* Reconnect the AC power cord.
* Power on the system.