Laptop doesn't work!!!!

Hello,

Whenever I try to turn on my laptop it shuts itself off and then turns back on by itself. It doesn't load anything because it doesn't stop turning on and off untill I force it off (removing power source). I cannot do anything with it at this point. It happened while I was watching a YouTube video and my screen looked like it froze so I (attemptes to) rebooted it and then this began happening. I beleive it may be some form of virus or Trojan. If you have any ideas on what to do I'd be happy to hear them! Thanks for the help! -Nate