E280(8GB) not responding

What I would recommend you to do is to format your device...
Formatting the player erases all files in the player, and oftentimes this is the best option to ensure that all files are removed and any corruption eliminated. Also, it is best to format the player when in MSC mode.
2. When the appears as a drive letter (under MSC mode), right-click on that drive letter and select "Format". On the "Format" pop-up window, click "Start" to begin the format process.
3. Follow the on-screen prompts and safely remove the player from your PC when the "Format Complete" display appears.
4. Unplug the player from the PC and when the player is powered up, the message "No Files" should appear on the player's LCD screen
5. Switch the mode back to "MTP", or continue to use "MSC". Note: It is best to use "MTP" when you are transferring subscription music to the player
Then I would recommend you to get the latest firmware upgrade for your device..To get the latest firmware upgrade follow this link...

http://sandisk.com/Retail/Default.aspx?CatID=1376

Thank you
Computerrep

P.S. Please rate accordingly...