I just replaced replaced my video card for one with more memory, after the last one fried I guess.
XP boots like normal, but if I open a video file, iTunes, Geometry Wars, PHOTOSHOP etc. ,
then I get a FLASH of a BLUE screen and XP crashes and reboots. 
Windows Explorer and other programs work, seems like it's the computationally intensive ones that crash
WMP works but not for video. 

I also just replaced the power supply with a much larger one, so I doubt it's that. 
It's really annoying and I have no idea what to do. 
Improperly installed video card?
XP64?

Specs:
Video Card:    EVGA GeForce 8500 GT 512MB
Motherboard: Gigabyte GA-8I945P
CPU                 Intel P4  1.6GHz
                         2GB RAM
PSU                Antec 500W



First you should MAKE sure that you system is really 64bit XP

I think the problem is you video card driver did not instatlled right,or you old driver did not remove wholly.
So , I suggest you to remove all of your old driver of you old video card ,and then reinstall the new one.

here is the Geforce 8500 site:
http://www.nvidia.com/Download/index.aspx?lang=en-us
wow thanks
I forgot to uninstall the ati software from the old card. 
computer 10.  me 0.