1: I can't turn on my Player.
Make sure unit is fully charged. Then long-press 'Play' button for a reset.
2: Player is not recognized by my Computer.
Make sure USB Cable is properly connected to Player and Computer and Player is charged.
3: There is no sound while Player is ON and PLAY button is activated.
Make sure Player is charged and audio files (songs, audio books) were downloaded.
Make sure earphones are properly connected and VOLUME + button is adjusted.
4: Sound was lost or weakened while swimming.
Probably water reached over eartips into your ear canals blocking sound.
Improve fitting eartips or use larger eartips (try use the triple action eartips while lap swimming).