Just in case anyone's interested, I finally got hold of the "broken" tablet and here's what happened:
-I couldn't turn it on.
-I replaced its battery with one from my working N800.
-The "broken" N800 turned on, booted and worked without any problems.
-I put the original battery back in the "broken" N800 and charged it. It took a long long time, something like ten or more hours to register as fully charged.
-After it was fully charged, the "broken" N800 worked fine with its original battery. Subsequent charges took a normal period of time, and I used it for over a week to make sure it was working okay. I couldn't find anything wrong with it at all, it switched on and off without any problems.
...so it seems that the N800 wasn't broken after all, but the battery had somehow gotten into a state where it took a long time to charge and this somehow made it behave erratically during boot-up. After that long charge though it worked fine and didn't require long charges again.
-I couldn't turn it on.
-I replaced its battery with one from my working N800.
-The "broken" N800 turned on, booted and worked without any problems.
-I put the original battery back in the "broken" N800 and charged it. It took a long long time, something like ten or more hours to register as fully charged.
-After it was fully charged, the "broken" N800 worked fine with its original battery. Subsequent charges took a normal period of time, and I used it for over a week to make sure it was working okay. I couldn't find anything wrong with it at all, it switched on and off without any problems.
...so it seems that the N800 wasn't broken after all, but the battery had somehow gotten into a state where it took a long time to charge and this somehow made it behave erratically during boot-up. After that long charge though it worked fine and didn't require long charges again.
Anyone know what might have been going on?