Unable to Delete Files(Music)

I’m unable to delete files from my Sansa e240. I deleted all the files displayed on windows media player list, however they are still on the device. When I plug-in to the computer, the screen in media player that displays all the contents on the device simply says there are no files on the device.  However, all those music files are still on the device.  Is there away to actually delete these files from the device? 

Try formatting the device

Thanks. I’ll try that.

It worked. Thanks a lot.

I have a Sandisk M230 MP3 player.  I cannot remove my song files nor can I format it.  I tried formatting in MSC mode but the computer message is that “formatting failed”.

Can anyone help me with this?