Please don't double-post on the forum. I don't think there are too many forums that allow double-posting. See Forum Rules (click here)

Is it a BSD (Blue Screen of Death) you see before it restarts?
If yes then it's generally a hardware issue. A component you have isn't fully compatible with the others or a driver is out of date. Graphic cards are a common cause. Forum links that discuss BSD worth a look thru are these (click on links): 1. Link 1, 2. Link 2, 3. Link 3, 4. Link 4

If not a BSD, then it could be due to your computer over-heating.
LW simply acts as the catalyst to set it off, but the underlying problem is there & it could well be any program that sets it off. Someone had a similar issue recently, HERE (click on link)