I think that if there is a problem with no power and a battery without power is replaced with a battery with power, this would help in most cases. It certainly helps me on the rare times when my N800 runs out of power in the middle of the night and I wake up to a dead N800.

The danger with some of these problem descriptions is that several different problem descriptions can be linked together and treated as if they are all the same. Thus, a user with a perfectly fixable problem involving a dead battery might become convinced that he has a more serious problem.

As for this "upgrade problem," I wonder what Nokia says about it? I've never seen this message, but it sounds like the kind of message one would get if downloading and trying to install something intended for the N810. As I recall, the official os2008 N810 software is less recent than the official os2008 N800 software, so one might get such a message if one tried to install the N810 software on the N800.