Just wondering, are you using Shift4 as your gateway? If so, there are a few options that could be misconfigured and you should call their (our) 24x7 support and they can help you. The Shift4 driver tokenizes the card upon swipe so if it's misconfgured, "credit card type not found" is the symptom.
If you are not using Shift4, then I'm at a loss. We have several 9700 Windows workstations here and setup in various configurations. I'm not aware of anything special with the USB or Magtek drivers were using -- actually I'm not aware of any Magtek driver at all being installed, I think whatever Windows detects (a generic HID device of some sort) is what we use.
Again, if you're a Shift4 customer, give us a call. The department that deals with these issues are MUCH more knowledgeable than I in nitty-gritty hardware stuff.