My friend just bought a used InFocus LP790 on craigslist and its having problems. He said it would not stay on for longer than a few seconds. I plugged it into the wall and it wouldnt stay on for longer than a few seconds. I plugged it into a surge protector (regular, nothing special) and i was able to get it to stay on for ten or fifteen minutes without it shutting off at all. As soon as i plugged in an rca video cable from my dvd player, it shut down again. I tried to turn it on while the video cable was plugged in and it would only stay on for a few seconds. Any ideas?