Windows Xp SP2 prpgress bar freezing

I bought a new grphic card upgrade for my computer last night and i followed every step according to the instrustions, and my system met the requirements to run properly. when i restarted my computer to switch to the new graphic card, all seemed well. Once i got to the windows loading screen with the little progress bar that loops around, it froze after 15 or more laps around and i cannot get my computer to boot any way possible. i have tried safe mode, which just brings up a system 32 error accross my screen, as well as repairing windows which also fails. any help?