Windows 7: computer no longer recognizes iPhone USB for Hotspot

Yesterday (and every day before) I plugged in my iPhone 5 (latest updates in terms of iOS) to my Windows 7 PC and used the USB hotspot capability. Today I plug it into my computer, turn on the hotspot, and my computer does not recognize the USB hotspot. No updates to iTunes, or Windows - yesterday it worked, this morning it does not.

Other data: the phone is charging via the USB connection. iTunes sees the phone via the USB connection. And I can connect to the computer via the wireless hotspot, so the hotspot itself is functional. I just can't get my computer to recognize the USB hotspot.

Tried repairing a file someone recommended in the Program Data/Apple folder (can't remember the name) and that didn't work. Obviously lots of reboots for both devices. Resest the network settings.

Help!

Thanks/