you have a horrible PSU. Replace it before your computer blows up.forget about the 500w rating its probably a max rating and i doubt the psu could live up to that. also read this http://www.tomshardware.com/forum/314447-33-6870-500w-gold-smps
Its an old psu and is also poor quality, replace it with something good like antec, seasonic or corsair. Also your 85C temp is a little high. Do you have any exhaust fans in your case? if you dont, get at least 1 rear exhaust fan.