Weird Problem!!??

Hi

Everytime since yesterday, my pc starts restarting by itself, if its out it starts up, but shuts down exacly, only if i start it manualy, it starts ok.
I tried a virus scan, it found some Malware and stuff but its gone now, but still happens. I tried a firewall, it went ok, but i got about 2000 blocked ip's in about 30 minute's!! And the game's were so hard to play because of the firewall lag!! so i uninstalled it.

What should i do now??

Thanks!!

 

Please, it keeps restarting, i'm getting all mad over here,!! Its soo irritating!!

 

Do you receive a message on your screen when the machine restarts are does it just kick off and reboot?

 

Yes it just restarts, i don't even get time to save my settings, its just 1....2 BOOM, out!!