I have a Gateway GT5678. I can turn my computer on and after about 20-30 minutes it completely shuts down. No beeps or flashes it just shuts down. I can start it right back up and it'll run 20-30 minutes and do the same thing everytime. Any ideas on where to start? This used to be my parents computer, but like everything else they buy instead of putting a little money into it to try and fix the problem they just bought another computer. It's been sitting in a room for about a year untouched so I decided to bring it in my room and see if I could figure out what it is. Help would be greatly appreciated, thank you!