I was able to intially install xp mode and virtual pc on my new windows 7, 64 bit machine. I did this to run software that is not compatible with windows 7. The computer had a registry error (due to xp mode or not - I'm not sure). I lost all my registery and needed to reinstall most of my software. I went to reinstall virtual pc and XP mode and receive this error message:
Cannot start windows virtual PC host process. Check system event log for more details. Class not registered.
I don't know how to get to system event log for more details.