I guess we are all Mac people and so don't know much about windows, but the activation seems to be driven by the fact that Vista sees new ACPI hardware - I wonder if Parallels could spoof the virtual hardware to look like the physical hardware and therefore take care of this issue? Or is there some way that we could stop Windows trying to install new drivers for ACPI, and that would be enough to stop the activation? Windows Vista seems to boot fine on the old ACPI driver even though it wants to install a new one . . .