MS Virtual PC 2007 cannot run on Windows 7 as long as Windows Virtual PC is installed. Uninstall Windows VPC and VPC 2007 should run.
To remove Windows Virtual PC:
- Open Control Panel.
- Under Programs, click Uninstall a program.
- In the left pane, click View installed updates.
- Under Microsoft Windows, double-click Windows Virtual PC (KB958559).
- Restart the computer to finish the removal