I'm not sure what the problem is, but one thing I try whenever I have weird problems with hardware, is make sure it has totally been turned off. In the case of the n800, turn it off, remove any sd cards from both the internal and external slot, and then remove the battery, and leave the battery out for a few minutes. Then put the battery (but not the sd cards) back in and try again.

You might have already done this, so ignore if you have. The one time I was having strange behavior on the n800, this did the trick, even though I had rebooted multiple times before and also flashed.