My series 3 seemed to be in the continual reboot mode. Finding that the most common problem was the hard drive, I replaced the hard drive (didn't format - maybe the issue), and that didn't seem to fix the problem although not all lights are flashing on the front now. I then changed the power supply, and now get a high pitched squeal, no powering up screen and tv says no signal, but all cords on Tivo and TV seem to be secure and correct. Is it the motherboard, did I miss a step, other? Thanks!