Suhas

No sound from H/K AVR-35

I apologize for the newbie question (I am an audio newbie).

The problem I have is that my Harmon/Kardon AVR-35 receiver has suddenly stopped emitting sound. I'm trying to figure out if there's something I can do to repair it or whether I should just throw it away and get a new one. Here's some facts/symptoms:
1. I bought it new in Fall 1999.
2. It went out a couple of weeks ago. One day, while watching TV, it suddenly stopped emitting sound. I tried turning it off and back on. When I did this, it played sound for a fraction of a second before going silent again. It did this a few times and now it doesn't emit any sound at all - even after power cycling.
3. All the other lights on the system seem to work. It doesn't seem to detect digital sources, though. Instead of saying 3/2/1 as it used to, the display continues to say "Pro Logic".
4. If I turn the volume all the way up to 5db, I hear a hissing sound from the speakers.
5. I checked all the speaker connections and there didn't seem to be any shorted wires or connections.
6. I don't know if this is related, but several months ago, I had an issue where the receiver would suddenly shut off if the volume got beyond a certain level. At the time, I was not using the subwoofer out and running my front speakers through the subwoofer instead. For a different reason, I changed this and wired the front speakers directly and used the subwoofer out to drive the sub and this problem stopped happening after that.

As I typed up point 3, I realized that I hadn't tested it with any analog sources. I'm going to try that when I get home.

Do you guys have any tips or advice for a newbie like me?

Thanks,
Suhas