I have xfx Radeon Hd 5770 ZNFC 1Gb graphic card for about the last two years along with cooler master power plus 500. Lately my computer crash every time it handles a heavy graphic/intense graphic, sometimes the sound still continues. So suspecting overheating, a applied new cooler master thermal paste to the graphic card but the problem still persist. And then i downloaded the latest driver and installed it and still it crash. And then i installed fresh copy of Windows 7 both 32 and 64 but the problem still continues. What should i do.