I use a Compaq nc8430 as my primary work laptop.  I was quite disappointed to find out that the Hardware Virtualization feature of Virtual PC 2007 was disabled and "not supported" on my laptop. 

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I asked around and was told by someone who will remain nameless that the laptop version of the Core 2 Duo didn't have this capability.  Thanks to Scott Hanselman, I now know that the capability is available on my laptop.  HP decided to disable it in the BIOS by default.  After I enabled it in the BIOS, Virtual PC uses it:).  I am not sure how much of a difference this makes, but it sure doesn't hurt!

-Marc