Could be it's all messed up from the loss of signal. I had lots of storms Saturday night and it locked up do to loss of signal (which is the only time my HR20 locks up). Could be yours didn't lock up but got some corrupted memory causing it to be weird. I would definately restart it. Heck I remember having to reboot my DirecTivo T-60 every 2 months or so because it would start to really.....slow.....down. Reboot cleared it up and it was fast again.
Not saying that you should have to restart but these are just computers after all and things happen.
Also, if you get blank at startup try to FFW for a minute or two and see if you get a picture, then RRW back to the begining. Again, something I haven't seen mentioned since at least March but that was a common way to work around the bug that existed back then.
Having said all that I'm leaning toward some corrupted memory do to the bad weather/loss of signal.