black screen and crazy video crashing

[AznAnarchy99]

I built a computer for my friend with

Core i5
Gigabyte P55-UD2
g.skill 4gb ram
ati radeon 5770
antec truepower II 550w
WD 640gb

From what he tells me it crashes everytime he is in game for any moment. Temps he says checks out fine. Im thinking it might be a power or video problem. I cant mess with it personally since Im back at school. Any ideas?

 

[cplpro]

Any further information would be nice (Windows Error Report, ...).

 

[mpilchfamily]

Could be video drivers or a defective PSU.