Enabling processor virtualization for x64 on Dell Servers
Sometimes, it is the most obvious things that really kick you in the fanny....
I was setting up a new Dell R610 in my lab. All my virtual machines were starting up just fine until I got to my Exchange servers. They kept just restarting over and over again. After a lot of troubleshooting, I remembered that I had not enabled the virtualization technology in the BIOS. That must be enabled if any of the virtual machines are going to be x64.
Open up the BIOS, go to processor configuration, then enable Virtualization Technology.