XP hangs on agp44.sys after interrupted update.?

Hi,

I recently upgraded a PC to XP SP3 for a friend, he was complaining about it being too slow afterward, so I offered some RAM I had laying about. I headed over to his house telling him to have the computer off when I got there. Apparently he never got around to install the subsequent updates to SP3, so when he shut down it went about doing so, and then just before I got there, he did a hard shut down by holding the power button for 5 sec. I get there, install the RAM, and the stupid thing is stuck in a boot loop, in safe mode it makes it just past mup.sys, a hang I've encountered before, to stop at agp440.sys, at which point it quickly reboots.

Any thoughts on how to fix this?