I have 4 tivos, and today the cable company showed up to give me a new premiere XL4. Sweet. But that meant shuffling the different units around. I move the HD from the bedroom into the office. When I plugged it in, I got the dreaded "powering up screen freeze." I happen to have a spare HD unit sitting in a closet (long story). It seems that the HD is usally the culprit and occasionally the power supply. I know that the service (lifetime) is tied to the motherboard, and the cable card is paired to it as well. I know I can replace the power supply to see if that is the issue (which I doubt, as it seems to be running ok). If I replace the hard drive with the one from the other unit, will it work or do I need to do some reformatting? I have a copy of instant cake but I cannot remember which model I bought it for. Thanks in advance.