My computer does not recognize the MP3 player

If you are using an USB extension or an USB external hub, get rid of it.

Try plugging the MP3 to a different USB port.

Try unplugging AC charger, and removing laptop batter for ten minutes, sometimes this can fix problems caused by accumulation of electrostatic charges on USB controller.

If that does not solve the problem, test a different USB device on the same laptop, and test the MP3 on a different computer. Either one may be faulty.

If the problem is the laptop you may fix it by removing and reinstalling USB root hub on hardware devices in Control Panel.