Sansa Fuze freezes during "refreshing media"

It freezes about half way through the “Refreshing Media” stage.  There isn’t a mtables.sys file in the root directory, and I have the latest firmware.  I can’t run chdisk because when I plug it in and go to Properties, there isn’t a Tools tab.  I assume this is because it’s in the wrong USB mode, but I can’t change that since it won’t boot.

Can anyone help me?