Keyboard not responding

[nin137]

i was trying to fix a problem on a co-worker's computer today. after she got a blue screen she turned off her computer. when she turned it back on the keyboard no longer responded. you need to hit ctrl-alt-del to get to the password screen and it does not respond.
the keyboard responds up until this point (i have gone into the bios and tried to boot from cd-rom). what was odd, was that even when i did a repair installation of win xp for her the problem persisted. i have tried everything short of re-installing windows all together.
any suggestiosn before i try this?
i also hooked up other keyboards just to make sure that it wasn't the keyboard itself.
the system is your standard office computer. dell original about a 2.1 ghz all dell peripherals (keyboard as well) with win xp sp2 installed. i ran the dell diagnostics but that foudn everything to be in working order.
i believe something must have screwed up with the keyboard driver when she turned off the computer, but i'm perplexed as to why a repair installation wouldn't fix that.
Thanks!

[ktkendall]

I agree, its in windows that the keyboard driver is hosed up, what about if you boot to safe mode?