seven instances of "Unknown device"
That is probably what is causing the problem.
Ok you need to count the number of USB slots you have on the computer.
For each USB slot you should have two entries in your Device Manager
1. Root (or something similar)
2. The name of the driver
Also don't know if you did this but try running the troubleshooter:
http://windows.microsoft.com/en-us/w...th-usb-devices
Also download USBDview
http://www.nirsoft.net/utils/usb_devices_view.html
Scroll almost to the bottom of the page and you will see download
This will tell us what USB devices are being used.