What do you do if your mp3 player stops working for no reason?

It will depend on what exactly went bad in the player. If it is still in warranty please contact the manufacturer. You can do some basic testing. If it has internal rechargeable battery check if it is not charging and needs a replacement. Is it getting detected by a computers' USB port. Whats the display showing if at all. Some times only the display is bad or display has some loose connections but the player plays music. For some players manufacturer provides firmware which can be reinstalled if it has got corrupted.

- Neeraj Sharma