You will need to reformat your clip.
But first you need to connect in MSC mode to the PC.
First reboot the pc.
Thenk Power off the clip and set the hold swtich to lock.
Press and hold the center button and connect to the PC with the USB cable (this will connect in MSC / recovery mode)
Next find the Sansa Clip volume on the PC and right click and format it.
Then , disconnect the clip and try to reboot it. Then go to settings>format> select yes (does a device level format).
Now you can connect to the PC and try transferring your content to the device again.
