Go to device manager, on Windows 8 you can do this by pressing the Windows key the typing, Device Manager
Find the USB controller that is not working correctly
Double click on the problematic USB controller and then choose "Update drivers"
browse my computer for drivers
let me pick from a list of driver's
Choose Universal Serial Bus Controllers
Ignore all options and Click on "have disk"
Click on "browse"
Choose ftdiport file, this is found in the folder with the rest of the vagtacho software, if you didn't unzip it please unzip it to the C:
Click on "Ok" and then Click on "Next"