I just want to say that I'm super exited about Virtual PC!
It's a fantastic product that I would have loved to have been using back in the old days when I was a developer. Using VPC as a testing environment would have saved me a lot of re-ghosting time on my test machine…

I was playing around with VPC the other day and after a while I found myself thinking: "I have a great base machine for developing, with W2k3, IIS, LCS, VS 2003, VS 2005 etc installed; I don't want to make it unstable by installing a lot of beta products…" So my natural reaction was to make a copy of that VPC and install the new stuff. Great, but then I wanted to install some other stuff, so I made a new copy of the base machine VPC, installed it and to make a long story short I ran out of disk space…
I now had 3 VPC with 15 GByte of data each that weren't all that different, wouldn't be cool if you could take the base machine, install the extra stuff and then just save the diff? Well it turns out the VPC can do just that!

1. Write protect the base machine hdd
2. Create a new Virtual Server with W2k3
   1. In Virtual Hard Disk Options select that you want to use An existing virtual hard disk
   2. Browse to your base machine VHD file
   3. Click Enable undo disks
   4. Finish the wizard
3. Click settings on your newly created VPC
   1. Change hard disk 1 to None
   2. Click Virtual Disk Wizard
      1. Under disk options select Create a new virtual disk
      2. Browse to the location where you want to save your VPC
      3. In the Virtual Hard Disk Options select the Differencing option
      4. Browse to your base machine VHD
      5. Finish the wizard
   3. Click the "Virtual hard disk file" options under settings and browse to the disk you just created.
4. Done!