If I change to "Other OS" or any flavor of Linux i get the same result. I've
changed the ISO to a W764 ISO as well with the same hang. More modern versions of Windows
Server boot fine, but I am not able to restore the backup with a version higher than
2008R2.
This link "https://bugs.launchpad.net/qemu/+bug/1593605" references a similar
problem that I am having and it's where I got the idea to pass the custom CPU flags.