The stupid dumb Christmas tree in our living room has been tripping the breaker lately and the Tivo has gone along with it. Before the day before yesterday, it had rebooted back up and started back as normal. Then, all of a sudden, it wouldn't revive. Here's what I did:

Unplugged, rested for 10 minutes, plugged back in. Stuck on Powering Up, A Few Minutes More, then returned to Powering Up...
Unplugged from the back of the box, and ditto.
Unplugged from the back of the box, rested, got the box to power up and work again, watched tv and recorded for about 35 minutes and then it shut down and reset itself again, got stuck in power up cycle.
Unplugged from the back of the box, unplugged the drive extender, divorced the extender from the Tivo, did NOT mess with it while it was divorcing the extender, then it got stuck on Powering Up screen again.
Unplugged again (after giving it 5 hours to resolve) got the green screen "The Tivo has detected a serious problem" screen, let it run its course overnight, woke up to Powering Up screen.
Repeated the above step, got green "serious problem" screen, then got the gray dead screen.

Trying to decide what my next step is. A new hard drive? I read on some of the forums about power issues and simple replacements within the logic board? (excuse rookie terminology) I have replaced a hard drive on a Tivo before with no problem but don't want to jump the gun on it until I know what I need. Any tips or advice would be SO appreciated!