I tinkered around with the new PC, and the problem is that the Skylake processor / motherboard combo doesn't support EHCI USB ports. Doy. I decided to just give up and install Windows 10, as you're supposed to be able to do that with a Windows 7 key. That didn't work, so I ended up in a chat session with a Microsoft muppet, hoping for a new key to use. He wanted to remotely connect to my PC, so I told him that wasn't going to happen and I'd figure out Windows 7.