Over a year ago, hang on let me check... my god it was 11th December 2006... my 7610 went blank, lit up, turned itself off and never came back on. It'd been turning off a bit before that as well. I bought a new battery just incase it was that but couldn't get it back on.
I don't remember finding how to perform the "green, * , 3" format back then but having found it tonight just tried it and it doesn't work. Very possibly because the phone has been sitting there dead for a year so obviously has no power at all. Would leaving it plugged in get some power into it at all? Nothing comes up on the screen of course.