PC flashed then shutdown

[SPuNKYbd]

I was playing the new splinter cell for a little while, when out of no where the screen flashed green then went black, then my fan started going really fast, i thought the thing was gonna explode. So i flipped the switch on the back of my psu, then turned it back on, and it started beeping rapidly, so i restarted it again, and now its running fine...

Im scared to start playin any games though, anyone know what happened?

Specs

M4A79XTD-EVO
XFX 5770
Corsair XMS3 2x2gb
WD blue 640
WD green 1tb
and a 650watt psu

 

[Atomic Rooster]

Overheated video card would be my guess. Check the temps on it.