I have Sansa® Clip+ Players 4GB I have tried the manual reset of holding the power down for 20-40s and then pressing it once more. It did not work. I have misplaced the original USB cord for charging but been using the mini USB that I had around. When I try to connect it to my new computer it says that it needs to be formatted but formatting will erase all the content. When I try just leaving it to charge nothing happens but the MP3 feels overheated.
Could be the cord you’re using is incompatible or the unit may be defective. I suggest you call SanDisk Tech Support if it’s still under warranty.