This may be slightly off topic, but I'm sure we will receive more and more VPC images from MS for miscellaneous AX setups in the future.
I have had this problem a few times, especially when working with two monitors. All of sudden Virtual PC just will not restore its windows. You can start the program, but can't work with it.
The cause is that VPC somehow stores totally weird values for where to open the windows. So when you try to open the windows they kind of do open, but with coordinates that is nowhere near your own neighborhood.
The solution is to edit the options.xml file located in the %appdata%\Microsoft\Virtual PC folder. In the <window> <console> section, you should change the values for <left_position> and <top_position>, for example to 10, 10 which would place the window in the top left corner of your screen.