Under Virtual PC 2007, there are two graceful ways to shut down virtual machines. The first is to shut down the operating system the way you would normally shut-off any PC. The second is to simply shut down Virtual PC 2007. When this RESTORE AT START option is checked (accessible via the console's FILE-OPTIONS menu), any virtual machines that were running at the time that Virtua PC 2007 was shut off will be restored to their most recent state.
For David Berlind's write-up on The Virtual PC 2007 User Interface, see his post
in ZDNet's TestBed blog.