I have had a 6100 that was totally dead, no startup chime, and so has at least one person on this board. And in both cases, they sprang back to life after a period of time, with no real explanation. Try washing and drying the board, reseating any cache, remove all off-board RAM, several dance rituals, and you should be good to go. It seems to be the time spent fiddling that eventually gets it to go.