I recently decided installed Server 2008 with Hyper-V on my laptop and migrated all my virtual PC machines.
If you use a Server 2008 32-bit vhd created in Virtual PC, you may not be able to install and use Hyper-V integration services. The mouse service will not perform correctly and your network devices will not show up. The VMbus will show a warning yellow icon in device manager and will say that there aren’t enough IRQ’s to load the bus.
In MSCONFIG, I changed the advanced boot options to check HAL when loading boot.ini and it fixed the problem.