One thing I've noticed is that sometimes updating your video drivers to the latest version isn't always the best way to go.
Try rolling your drivers back one version that has been release for a little while ( thus has been optimised ).
Also, your comparison between XP on your computer, and XP on your friends computer isn't valid, as XP is a M$ product for starters, so that casuses a problem, lol. Also, all the XP updates that might have been installed on your version of XP can bottleneck your system something feirce...
Hope I Helped...
Jess.

Team EOD :: Programmer/Logical Engineer/All-Round Nice Guy