That's why I suggested booting to the Windows disk.  If by some chance it IS the video card, as soon as windows starts to load the GUI, he will get the same issue.  The problem with your system was the power supply, not the video card.  This isn't the case here because he WAS able to boot up before W7 got trashed.  First losing a piece of software and then the OS could be anything from a messed up driver, to a completely hosed registry to a virus.  But if it was working fine up to the update, it is probably not going to turn out to be hardware.  At least not video.