I have been just dealing with this problem for a while now but finally got tired of it. When I turn my computer on with my keyboard and mouse plugged into the usb ports, my computer boots to the bios screen and never makes it past it. If I unplug the keyboard and mouse from the usb ports and let it boot to the windows xp loading screen and then plug them back in it boots all the way and there are no more problems.
Processor - AMD Athlon 64 Dual Core 4000+ 2.41 ghz
Vid Card - BFG Geforce 7800 GTX
2gb of ram
MB - Fatal1ty AN8 SLI Socket 939
Windows XP Professional 64 bit 2003