mp3 player will not load music from computer.

my memorex mmp8001 works fine exept for when I plug it into the computer. when connected, it loads slow and when i try to add a song on it, the computer screen eventually freezes and will not add the song to the player.i have tried resetting the device, letting the power drain, and have also tried it on diffrent computers with the same result. this just happened all of a sudden and i have no clue whats the matter with it. anyone know whats wrong?