1. Confirm virtualization is enabled in the BIOS.
2. From the hyper-v host, open an admin cmd prompt.
3. Enter: bcdedit and review the output. There should be a line for hypervisorlaunchtype Auto
4. If that entry is not present, enter: bcdedit /set hypervisorlaunchtype Auto
5. Enter: bcdedit and the line should be there.
6. Reboot the hyper-v host.
7. Once the machine has been rebooted, try to start the virtual machine.