Today I had replaced the battery, a AAA Duracell coppertop, in my MP3 player, a 2 gig Sandisk. I tried to turn on the player and nothing happened. I kept pushing the button and then decided that the battery must have been dead. I pulled the player out of the holder and it was very hot. I immediately pulled the battery out and it also was extremely hot. My first thought was that somehow the player had burned itself out, but I put another battery in and it played, and is playing just fine.
My deduction is that it was a faulty battery. Has anyone else had this happen? Really weird.