this just happened to me--power went out. when it came back on, it was 1904.
ijust got this imac at christmas......is it possible this battery thing is already dead? if so, do i actually have to pay for a new one? sounds like a bogus battery to me.
also, i keep getting this strange error message on startup, saying my "network time" and "timezone" are incorrect......is this related to the battery issue?