Changing Serial Number
Fog doesn't have native support for this but Microsoft has released a tool to change the Windows CD Key/serial number. It can be downloaded from:
The Genuine Advantage Product Key Update Tool is only valid for users attempting to change their current non-genuine Product Key to a genuine COA sticker or genuine Product Key - all without a reinstall!
If the image you have installed is not activated you can also use this option:
Run c:\windows\system32\oobe\msoobe.exe /a
Choose activate via phone.
Choose Change product key.
A third option is to install sysprep from Support\deploy.cab on the Windows CD.
With this tool you can reset the product key.
You will be asked to input the product key on the first reboot of the machine.
If you image the computer in this state all the computers you image will have to input the product key before the computer is useable.
This option applies only to computers with pre-installed, OEM keys
Another option is to install Windows with the following key for Windows XP 32 bit edition: MVF4D-W774K-MC4VM-QY6XY-R38TB This key tells the machine to use the OEM key installed in the motherboard For more information on this please read the following link: http://technet.microsoft.com/en-us/library/bb457078.aspx