1. Click Start, click Run, type services.msc, and then click OK.
2. Double-click Plug and Play.
If you receive a Configuration Manager message, click OK.
3. In the Startup Type list, click Automatic, and then click OK.
4. Close Services.
5. Restart the computer.
or
open control panel and double click on add/remove programs/software. Look for a program named contextplus and click on it and then change remove(uninstall) and reboot. Check device manager and make sure your devices are listed.
or
Look here