first 2 things he should do to test are 1. remove the card, re-insert it making sure that its in securely 2. try it another pc
edit: it just occured to me that it could be a problem with a corrupted driver although i think its unlikely as that would normally only cause a BSOD on something like a graphics card but it is still a possibility. press F8 repeatedly as the PC is starting up until the screen with the option to start in safe mode comes up. start in safe mode and see if that works. if it starts in safe mode i think that would suggest a driver problem in which case he should use safe mode to remove the drivers and reboot into normal mode and try re-installing them, perhaps downloading updated drivers