Korg Poly800/EX800 Users

hello Hawkers, last night i had a sequence running on my hawk when the whole thing crashed. i am hoping that someone here can help me troubleshoot what happened and how i can go about fixing it.

what happened was i was playing around with the advanced seq. mode, which i havnt really done yet.  i had a sequence going, which was clocked externally.  I hit "Bank Hold" and "Write" at the same time, (thinking that i could change the sequence.. i was really just playing around with it) then it started flashing a bunch, and reset.  after the reset, it goes through the self check, and gives me "error 4" (no error 5 or 6) which i understand is a hardware issue, and after that it just loads a "1" or sometimes an "A".  the strange thing is that i had it had a total running time of about 20 hours with no trouble, and it hadn't moved from its spot.  i can still access the tools function, but there is no sound or patch banks anymore.  everything up until this has worked flawlessly.  Did i erase everything?  if so can i just re-flash the operating system back on it and reload the patches?  im not sure how i can check for hardware problems...  and if i
 re-flashed it, do i need to change around the positions of the IC's first?  any advice that's offered would be greatly appreciated. 

thanks much, 

ianb