Sansa e250 Not working
I've had similar problems. You should reformat the player and install latest firmware from Sansa. (See below)
(There is an option to format the player w/o installing new firmware. Copy an empty file named sansa.fmt on the 16mb drive and unplug usb. The player formats and restarts. This is an unofficial solution that solved my problems, since my Sansa got totally stuck and would not accept the procedure below.)
New firmware: download the latest firmware .exe file from Sansa site
Once you have downloaded the file, please follow these instructions.
1) Double click on My Computer so that you can see it on your screen.
2) Turn the player off.
3) On the top of the player is a Hold switch, move it to the right (toward the headphone jack) so you see Orange.
4) On the left hand side of the player is a Record button, press and hold it while connecting the player to the computer. Continue holding the Record button until you see a new icon under My Computer called 16MB FORMAT. Once you see that icon you may release the Record button.
5) Double click the file you downloaded earlier and run it. Follow all of the on-screen instructions, and when you get to the prompt where it asks you whether you would like to Format it, choose Yes. Once it is done, click Finish.
6) Disconnect the player and look at the screen. Several things will be displayed, and when you see Key Lock, System Shutdown, move the Hold switch on the top back to the left.
7) Turn the player on and watch the screen. If you see a Refresh Database Fail error, you will need to follow steps 1-7 again until you do not get the error. If it does not work the first time, it could take up to 3 times for it to work.
good luck /Par, Stockholm, Sweden