What type of PC, Purchased or you built, What kind of mother board. What kind of proceesor, Any cd drives etc.. In order to dtermine if it is your power supply we need to know how much power your pullin for that psu. Also, to check compatibility of graphix card to rest of system.
"Research is what I'm doing when it looks like I'm not doing anything" :D
BEER, is it in you?