For DRM capabilities, you need Media Transfer Protocol (MTP) operational. This is an integrated part of Windows Media Player 10 and later.
If you have WMP 10 installed, first select MTP mode on your Clip+ by going to Settings > System Settings > USB Mode > MTP. Plug in the Sansa.
Open a windows explorer window (My Computer) and have a look at the Clip+ in this window. Is it displayed as a Clip, with an icon, at the bottom of the list, under “other”, as a media device?
Open the Device Manager and locate the Clip listed as a portable device. Double click or right click on it, then select uninstall. Unplug the Sansa, wait a little while, at least 15 seconds, then plug in again. Windows will reinstall the correct MTP driver for you.