Article to read to give you an insight into the BSOD (Blue Screen of Death) as it is referred to. Basically your computer is telling you that it didn't like something. Did you install something prior to this happening?
As I said before "Basically your computer is telling you that it didn't like something that occurred" and shuts down to prevent "damage". It is not always easy to establish the cause. System Restore has no doubt done it for you and you may NEVER see the BSOD again !