First had 3 red rings, realized it was overheating, fixed that, months later got 3 red rings again, this time it's an 0101 error, solved that by holding sync button, then power on, keep holding sync for awhile, then power off. Power on, no more red rings, middle green light stays lit, but no video and no sound.

Found out that my connection on the back of the 360 HDMI input connector wasn't making good contact, when the hdmi cable is pushed all the way in, gets no video and no sound. When I pull out the HDMI a little, like half way in, I get video and sound. I made the HDMI connector stay put half way and can't wiggle at all by using a sealing sticky foam spray around the connector and making the foam stick the the 360 plastic casing.

The no sound no video error might be a common problem, always test using the RGB cable to see if you get video and sound. I lost this cable so was stuck trouble shooting this. It wasn't a hardware problem at all as suggested by some forum members replying to others. So if you're using HDMI and get no sound and video, try my solution.