Does this sound like a GPU,CPU or RAM issue

[alandalf]

I play sims 3 alot and it performs perfectly on my GTX 260 but for some reason it randomly just closes and goes to the desktop every few hours.
I have an i7 920 OC'd to 3.5GHz and 6GB corsair dominator @ 1450Mhz the GPU is at factory settings.
What could be causing the instant closure and just going to the desktop?

 

[Ubrales]

I had a similar issue with gaming. I traced the problem to a low CPU voltage. I increased the voltage (RAM voltage too) well within manufacturers' limits and the problem was solved. My i7-920 is now running at 3.82GHz and the core voltage is set at 1.275V (actual 1.270V) , and the Corsair Dominator RAM is set at 1.550V (actual 1.570V)

It may be possible that your voltage settings are on the marginally low side. Increase them slightly and stay well within the manufacturers' limits.