Black Screen-Need information

For the last month on random mornings my TiVo has greeted me with a black screen. TiVo 'non' support is of no help. All they have done is tell me to unplug it for 20 seconds plug back in and if it happens again then I can pay $150 for a new one. This is already my 2nd box in 4 years, my first suffered from a dead hard drive. I think the power outlet might be the factor but TiVo won't help me trouble shoot. Since it is not under warranty anymore all they care about is my money not my satisfaction
I have done the 57 thing on the remote on start-up and that didn't help. Does anyone have an idea what the problem could be or if there is a utility I can use to diagnose the problem? My TiVo is connected to my network and I wasn't sure if someone designed a utility that could check the box for problems from your computer.