►Not an answer but a really weird development.
My Optiplex 7010 is actually a dual-boot machine. I have both Win 7 Pro 64-bit and Win 8 Pro 64-bit, on separate partitions in the hard drive. Win 7 was first, and I installed Win 8 later. The problem described here is in Win 7.
All of the above bad news was from running havdetectiontool.exe from Microsoft while in Windows 7 Pro 64-bit. HOWEVER, when I booted into my Windows 8 Pro 64-bit, the havdetectiontool.exe says I DO have hardware virtualization!!!
So, not enabled in 7 and yes enabled in 8 - ON THE SAME PC WITH THE SAME BIOS SETTINGS !!!!!
What is this? What is the problem?
I need it OK in 7 because I want to do XP Mode in 7. What is the crucial difference between 7 and 8 on the same PC ???
[One more detail: When I first tried to run the havdetectiontool.exe from Microsoft while in Windows 8, it gave me an error message that it could only run in 7, so (while staying in Win 8) I set its Properties to compatibility for 7 and Administrator privilege level. That's when it told me that hardware virtualization IS enabled. But when I ran exactly the same tool again in 7, I got the negative info posted above.]
Help !!!!!