Paul O'Neill -- founder of the Trans-Siberian Orchestra -- was stiff and clearly non-revivable when a hotel employee found him and called 911.
In the emergency call -- obtained by TMZ -- the dispatcher tries walking the employee through how to perform CPR before abandoning the plan after determining the body was "stiff."
As we reported ... law enforcement sources tell us there was no sign of foul play, and it's unclear how long he was deceased before cops responded to the 911 call.