This is very strange, but I have a faint memory of somebody else reporting a similar problem not long ago (years ago?).

In your case, you said that the buttons (front panel?) *do* work until the player decides to go standby. That is a good sign, as it means the hardware is probably fine.

Next step is to connect via serial cable (ckermit, hyperterm, whatever), and hit Control^C to get a shell prompt on the player, after it finishes booting up. This should work, though it may take a few seconds.

At the shell prompt, try player -i to reset the saved settings.

Cheers