I can play cryis 2 for an hour or maybe 2 if I'm lucky until the monitor goes black and says no signal, It will not come back on until I restart my computer and it only does this with crysis 2. I can play any other game just fine. I just bought a new lcd monitor so I thought maybe the monitor was bad so I plugged my old one back in and it did the same thing after about 30 minutes. I have tried different cables with no luck, I have checked all my connections inside and out of my system and everything is good. I have re seated my video card to make sure it had not come loose. I cleaned all dust and debris. I have also checked the temperature of my video card and CPU in game and out and the temperature was normal for both. I have the latest updates and drivers for everything. Here are some of my system specs. Any help would be much appreciated. Thanks

Windows 7 Home Premium 64-bit
AMD Athlon II X4 630 2.8GHz AM3
4GB DDR3 1333MHz Memory (2GB x 2)
MSI 760GM-E51 mATX Motherboard
Radeon HD 6850 1GB GDDR5 PCIE Video Card
500W ATX Power Supply

Sounds like the GPU is overheating and killing itself, either that or a power issue

What exact power supply do you have?

You need to consider the power on the 12v rail MORESO than the total stated wattage!

is it connected with HDMI?

You're having the "forced to 24hz" issue.

I believe my power supply is an ULTRA LS500, I know its cheap and Its going to get replaced as soon as I have the finances for a nicer one. Yes it is connected with HDMI.