1. Boot into safe mode and then restart and boot regularly. See if that helped.
2. Restore the system to a point when it was recognized.
3. Here's something I read: Start your computer in safe mode and open the devices and printers there. Right click on the window. Set View to Large icon; Set sort by - name; Set group by - classification; then exit and restart your computer to normal mode. Open your devices and printer tab and all the devices including printers show up. Operating system Windows 7. Hope this helps because I experienced it.