No devices are listed in Device Manager

It would appear that you have acquired some Malware on your system. Posted below is a link along with instructions for using the tool.

This should help!

Download AproposFix from the link below to your desktop, but do NOT run the tool after downloading:
Reboot your computer in Safe Mode, here's how:

1. Restart your system
2. Once you hear a beep during the startup, but before the Windows icon appears, press the F8 key on your keyboard.
3. Additional options should now appear. Select the first option, which is "Run Windows in Safe mode".

Once in Safe Mode, double click the prior downloaded aproposfix.exe file and unzip it to your desktop. Open the aproposfix folder on your desktop and run: RunThis.bat. Follow the onscreen prompts.

When the tool has finished, reboot your system to normal mode, and post the entire contents of the log.txt file in the aproposfix folder.