Cool! Yeah... that one.
I don't have the wireless controller. What I did was:
Device Manager > Human Interface Devices > Xbox controller > Update Driver Software > Browse My Computer > Let Me Pick >
I made sure, 'Show compatible hardware' was selected, and then double-clicked on the, 'HID-compliant game controller' item under, 'Model'.
After that, everything started to work again. Of course I can't find the XBox controller in the list any more (it's hidden amongst all the other, 'HID-compliant game controller' items).