PC Problem- Restarts

Hi guys

Got a problem with my PC that REALLY annoys me

When I turn it on from cold, itll just randomly turn off for no reason after 10 minutes, but then, if i turn it off and on again itll be fine

I first thought it was a heat problem, as it was running very hot, but it cant be. Ive tried it with no case on and it still does it after 10 minutes, yet if I then restart it, even if its crunching UD all day, it wont reset, even if I have it on for 10 hours.

So is it a problem with my motherboard? It seems to be almost timed to 10 minutes to annoy me but then its fine unless I leave it off for a couple of hours. I've honeslty no idea whats causing it, and even though it runs hot, it cant be the heat due to the patterns of how it does it.

No one? :(

I had that until I updated my version of Catalyst.

Only other thing I can think of is the temp. until I reseat my heatsink I can't use my PC in this weather.

Its not catalyst, Ive been using the same drivers for about a year with no problems, until now :(

what ram do you have and sppeds please