Alienware M17x R2 Random Daily Reboots and Rare Freezes

Hey People.

I've got a Alienware M17x R2 a few month ago and even since i got it even brand new out of the box i've been having issues with it just rebooting itself at random.

For a while it seemed to be gone aftrer i updated all my drivers from the Dell site, but then it came back..

Any idea what might cause this?
All that happens is in the middle of doing anything (or being idle) the screen flickers white then reboots.

I've also got some random freezes that happen very rarely, but the random reboots are my first issue as i work as a graphic designer and having my day's work be lost is kinda a bad thing.

Any Suggestions?

Thanks.

 

My System is:
Alienware m17x r2

8gb RAM

500gb SSD

NVIDIA GeForce GTX 285M SLI

Windows 7 Ultimate x64

Intel(R) Core(TM) i7 CPU X 940 @ 2.13GHz