Well, that supply is rather crappy, but you can read it's label on newegg.
12v @ 13A and 12v @ 8A, so 156W and 96W, of course that is probably rated at 25C, so the instant it is turned on it is probably out of spec.
7750 can't pull more then 75W, but your CPU is rated at 95W, plus the motherboard, drives, and fans. probably is very close to the maximum limit, and of course any added heat is going to make it worse.
A new powersupply would be a wise option.