- Uninstall the nic via Device Manager. Check the "Delete driver" box.
- Follow this to disable automatic driver installation. (That procedure only works on Win 7 Pro+)
- Either re-scan for devices in Device Manager, or reboot your system. (I chose to reboot)
- Once restarted, verify that the nic shows up under "Unknown Devices" as an "Ethernet Controler".
- Revert the change you made in gpedit so you can install the correct driver now.
- Install the appropriate version of Intel's drivers/utilities for your card.
Hope I save someone out there some time.
** ADDENDUM **
I upgraded the Intel drivers recently, and after that I was back to my original issue. Turns out I also needed to uninstall VirtualBox to get things back to working.
** ADDENDUM ** ADDENDUM **
Actually, if you do not install Host-Only networking in Virtualbox, the problem doesn't appear.