The m200 series is a really, really old (over 5 years) player and not too many people that frequent this forum are familiar with it any more.
Taking the battery out and re-inserting it should force a “hard reset”. Make sure you leave it out for a few minutes to let any residual information stored in memory to dissipate.
With all the different issues you’re having though, I’d probably recycle it responsibly and get a more modern player.
