Is it my Power supply??

Ok. I have a system that keeps rebooting on its own. Only time it seems to do it is when i have been playing a game for about 5-20 mins and whenever i try to use my cd drive. I have ran multiple virus scans and checks. I have fully updated all my drivers with correct digitaly signed drivers and still keep having the same problem. Whn the problem first started i was getting the B.S.O.D. popping up with a error message and dumping physical memory. After i updated my Drivers and Windows the error screen quit comming up but the Pc still restarts on its own. It seems that the only time it does it is when something needs to pull a lil more juice than idle power. Could this just be a power supply problem?? i also have ran couple different registry cleaners too and fixed all errors. The power supply i have is putting out alot of power. Its powering 3 fans and a cpu fan Plus L.E.D. lights inside the tower,DVD drive,MOBO, and Hard drive.Power supply or something else??