I have Windows 7 Virtual PC (64-bit) with Windows XP Mode in my Win7 Pro x64 host setup. When I first installed both programs, I had no trouble shutting down or restarting XPM...
...But just recently, after a restart, my VPC crashed. The sequence is as follows: After shutting down XPM, the window disappears, to be replaced by the typical scrolling green line with the message "Shutting down the virtual machine..." The message changes to "Starting the virtual machine..." as it attempts to restart XPM; and just as it is about to open the XPM window, the error pops up,"Windows Virtual PC has stopped working".
At that point, I am obviously forced to shut down the process. The only way I can start XPM is from a cold start. I cannot perform a restart of any kind, whether it is a cold restart or a restart following the installation of a program that requires a restart. I have to shut it down cold before I can start it again.
My first suspicion is that I installed a program that caused one of my Win7 components (whatever is required for VPC and/or XPM to function properly) to malfunction or disappear from my setup. But I have yet to notice any other program exhibit abnormal functionality or crash completely. Nor have I tinkered with the registry.
I tried removing VPC and reinstalling, but it still crashes when I attempt to restart XPM. I have not yet tried removing and reinstalling XPM as of yet, but I suspect that might not work, either.