From
http://developer.intel.com/design/mo...ndardbios.htm:
"IMPORTANT!!! Enter the "BIOS Setup Utility" by pressing the [F2] key during boot..."
It confirms that previous posts are right.
IF you still have a problem, here's my 2c:
Remove NIC. Intel 845BG does not have an embedded NIC.
Reboot PC, press ESC to remove Intel logo then F2.
If not, remove battery. It must get you to BIOS to setup time, at least.
Good luck!