After trying many things including getting the product team involved in diagnosing the problem, I decided to rebuild the server from scratch. That seemed to correct the problem of Hyper-V not working correctly. No one is sure why, but my guess is that the install got corrupted for some odd reason.
I have to say, though, that getting the product group involved was kind of cool even though they couldn’t help – which wasn’t their fault, but the fact that I didn’t have the equipment to do the kernel level debugging that they needed to do.
Now, however, the web site is back up and running on the new Hyper-V box!