How to fix colby mp3 player not being detected by computer?

i plugged in a colby mp3 player to the computer the computer does not recognize it. I can not download anything to the computer. The computer is a public one and anything i download has to go directly to the mp3 player, as i can not get to device manager the computer belongs to a public library the mp3 player worked before but i deleted all songs off it how can i get it to work again i do not have any cd for it