Recently, my computer has been turning itself off. When I turn it back on, the computer either boots up then turns off after a non-consistent matter of time, or it just turns on and doesn't boot. I've opened the computer and checked all 4 fans that are inside, all of them are put on correctly, and I've read everyone free thread I could find online. If I'm lucky, the computer will stay on long enough for me to log in. When i did, I started up my anti-virus, and as soon as it got halfway, it shut itself off. It all started when my cousin came over and connected her Sidekick phone to my computer to transfer music. Ever since then, it's been acting like this. Is there anything I can do to fix it?