PC goes into "Sleep mode" while playing games


Aug 14, 2012
I'm not sure if someone else has already posted a problem like this but here it goes: While playing rather high-end games my computer after about 5-10 minutes goes into "sleep mode". Meaning the screen goes black, the PC fans get louder or spin faster, the audio goes out, and the light starts blinking. Only once has the audio gone into a loop. I seem to have fixed on a couple games by running them in windowed mode but the same problem still occurs on other games. I've tried blowing out the dust with compressed air but that didn't work either. This problem has NEVER happened before with the games until recently. I haven't made any changes lately to my computer, and my video card is completely up to date. After this happened and I've restarted the system is says my temp. is around 30° Celsius and no components seem to have melted.

My Specs:
OS Version: Microsoft® Windows Vista™ Home Premium, Service Pack 2, 64 bit
Processor: Intel(R) Core(TM)2 Quad CPU Q9400 @ 2.66GHz, Intel64 Family 6 Model 23 Stepping 10
Processor Count: 4
RAM: 4094 Mb
Graphics Card: NVIDIA GeForce 9600 GT, 512 Mb
Hard Drives: C: Total - 305242 MB, Free - 18774 MB;
Motherboard: BIOSTAR Group, TP43D2-A7

Should I attempt to do a full computer clean? What might cause this issue and are there any solutions to it problem?

Thanks in advance.
sounds like your gfx cards vrm is getting hot. run gpu-z and check the vddc temps. a m8 had this issue with his 4870 and was unable to fix it even by cleaning, installing and adjusting the power mode..

if the temps are way up there than you may want to use msi afterburner to set your fans to a higher speed at lower temps... this should help reduce the overall temp of the card and reduce the load temp on the vrm modules.