Android USB not recognized on PC
This is definitely being caused by the drivers. You have to uninstall everything related to your phone from your computer. The drivers, and anything else it installed. Remove all of that, then re-download the drivers for your phone off of google. Install these drivers, then plug the phone in. It should download anything missing now and hopefully recognize the device. 

You could even try reinstalling the USB device's drivers itself.
On my phone, I can specify whether to host the android device as media storage, image, or charge-only. Try switching between these (if your device allows) and see if that makes a difference.

EDIT: Using DriveDroid, creating an image and hosting that image as a USB flash device would be an appropriate workaround.