well i bought mine from ebay too and it did come with a warranty.. so you didn't buy a berlin-shop unit
dunno how to remove the battery but someone else had to do this. maybe unscrew the back of the device and so on...
doubt there's any replacement battery available... a bsquare product manager said so to one of my friends..
the reset switch... i was afraid of that myself.. when i broke the stylus tip into it...
(or not into it, but i have never been able to find the tip since then
)
since then i'm not using the stylus to reset it
(found an excellent method, unique to me, sorry
)