I understand the desire to figure out what's causing that very strange behavior, but allow me to suggest that you grab one of those $79.99 WD20EARS from newegg (if the discount code hasn't expired) and use the instructions here
http://www.tivocommunity.com/tivo-vb/showthread.php?t=462179
However, first you might try grabbing another 160GB or larger drive, dd (or dd_rescue) the original to it, and try it in the TiVo to make sure there's really nothing wrong with the original. As contradictory as it sounds, a drive that actually works in the TiVo isn't necessarily good.
One other thing occurs to me. Perhaps your power outage damaged your power supply just enough to let it still run the original drive but not quite run the 1TB.
http://www.tivocommunity.com/tivo-vb/showthread.php?t=462179
However, first you might try grabbing another 160GB or larger drive, dd (or dd_rescue) the original to it, and try it in the TiVo to make sure there's really nothing wrong with the original. As contradictory as it sounds, a drive that actually works in the TiVo isn't necessarily good.
One other thing occurs to me. Perhaps your power outage damaged your power supply just enough to let it still run the original drive but not quite run the 1TB.