No sound is coming from my Yamaha HTR-5460. It was working fine until one night I wanted to watch a DVD and no sound would come from the speakers. I noticed that a small "ps" is now appearing on the receiver's display. I've also noticed a small glitch (line) on the far left of the display that should not be there. I tested it with the tuner, the TV, a CD, and still no sound. I've had the receiver for about 2 years and it has been a great receiver. Any ideas on what could be causing this problem?