First question is the BSOD STOP code/error message and PC configuration.
Problem is, in XP, the BSOD's specific to the GPU don't exist, making GPU hardware problems harder to diagnose. The fact the crash apparently occured within that ATI driver is a good reason to suspect the GPU though.
First thing to try is a different driver version. If the problems persist, the next step would be to try a different GPU or RMA the one you currently have.