Was running Virtual PC on an XP box and have now moved to a Windows 7 x64 box. Moved over the 18mb (yes, mb!) VHD file that is running a DOS application. Set up a new VM, pointed to the VHD file and it runs fine. Problem is that is runs nearly 5% as fast as the old XP box running Virtual PC. Where keypresses were instantly recognized they are lagging now. All the settings are the same. Obviously no integration services installed.
Virtualization is turned on in the BIOS of the PC.