using Windows Media and Sansa Express

When I first got my Sansa Express I plugged it into the computer, opened Windows Media Player and put music on it easily. Now whenever I try to put music on the Sansa Express it won’t copy the music and give me an error message. Is this something I can fix on my own?

What is the error message??

all it says is “an unknown error occured”

I haev the same problem !!! pls help

you can try to reformat it, and then reload the music.