Desktop restarts on its own

[tsetze]

Be it when I'm doing the startup repair, or during system restore, or halfway in a dota game, or just simple idling, it will auto restart.

Happened only these two days which I haven't installed anything except plugging in a thumb drive which I plugged it in another laptop as we'll.

Restored to the earliest restore point and it didn't work as well.

Any solutions to this?

Thanks in adv