Please help me?

Re-install the software that came with your Sansa player and see what happens then.

Heres something that worked for me....when I first got my e280 it worked fine then one day it just stopped.. After dealing with sansa customer support several times without any luck and trying everything else I could find in various forums, I came up with something that works for me....1st, if you are running vista, the device has to be turned of when you plug it in. If that does'nt work, try putting your sansa in lock mode...with it turned off plug it in to your pc and hit the power button until it turns off the push it again until it comes back on I did this several times and It worked and it continues to work....Good Luck.