Help blank screens during gaming

[westwardfilly5]

I finally built myself a PC a about a month ago and it was running fine up until now. During gaming my monitor goes blank and then tells me no signal and I have a weird audio glitch for about 3 seconds then it stops and to have my screen reconnect to my PC a have to restart my computer. I have tried playing many different games and every time it happens cod waw, crysis 2, dirt3, i even tried tf2 to see if a much easier game to run affected it. i have run crysis 2 ( my most demanding game) in windowed mode and monitored temps of gfx card it maxed at 76c i have tried reseating it and i still have no idea of what the problem is or why its happening.
I have a
FX 4300 @ 3.8 (stock)
cooler master hyper 212 evo in pull
asrock 970de3/u3s3
Gigabite 6870 factory oc'ed
8 gb of corsair vengeance ram @ 1666
600w corsair gaming series psu
1tb hard drive

Edit: i am using a dvi to vga adapter because of old screen

 

[hytecgowthaman]

If u r system (processor,gpu,smps)fan has any damage the system overheat quickly so protect from more damage the system shutdown without any error message like bluescreen message.
so check all fans are working correctly and clean the dust from cpu.

 

[westwardfilly5]

Everything else is in brand new and working condition and when it happens the pc stays on its only the graphics card that dosnt seem to stay on or at least continue working