I have a Series 3 and it started acting up a couple of weeks ago--would reboot itself, OS in general was incredibly slow, etc. Finally things got to a point where all the TiVo would do is reboot itself in an endless loop. It would show the "Powering Up" screen, then the "Almost there ..." screen, and then would reboot before getting any further.

I purchased a replacement drive from WK which I installed today, but the TiVo is exhibiting the exact same behavior. Shows "powering up" and "almost there," and then reboots again. If I leave it plugged in it does this endlessly and never gets further than the "almost there" screen.

I haven't had the cable cards plugged in for about a week, and even without the cable cards it still behaves the same way. I am using the wireless network adapter but unplugging that didn't make any difference.

Any ideas why it might be behaving this way? Does this mean there's something more serious wrong with the unit itself? Would the next thing to try be the power supply, or am I wasting my time/money at this point?

Thanks for any ideas anyone has.