Korg Poly800/EX800 Users

I think my beloved Poly 800 might be close to death. About two 
weeks ago when accessing parameter 86(receive chanel) 
instead of a two digit number, the display read P1. Somehow the 
first number turned into the leter P??? A few days later, I turned it 
on to find out that the memory has been erased. Now, it dosn't 
seem to respond when I try to reprogram it? I'm thinking that one 
of the chips or the internal battery went bad. Can anybody tell me 
what I could do to get my P8 working again?