I cannot find the music that I transferred into my player
The song might be in a format that is not supported by the player. Only MP3 and WMA files are supported.
The audio file might be corrupted, try to playback the file on your PC first, If it does not play, RIP the song again.
When a WMA file has been protected within Windows Media Player, the files are then unable to be copied and sent to the player. This will cause the files to be seen within the Windows Media Player library, but will not appear or playback within the Digital Audio Player. When ripping your music from CD, please always make sure that the "Copy-protected music" option in Tools->Options under Rip Music is unchecked.
Some of the music tracks may be in a format or bit rate that is not supported by the player such as AAC, or files with a variable bit rate may be skipped by the player. (For MP3 the player supports 32 –320kbps & for WMA: 5-192kbps with sampling rate 8.0kHz up to 48kHz)