Many times when I start working at a new customer I find a few copies of XP that have a pirated serial number, or the same number used over and over.

Right from the start I make sure the customer purchases the proper licensing from Microsoft – It only takes one call from an angry employee to cause the company a world of grief.

In these situations it is nice to change the machine to a valid serial number without having to totally re-install the operating system.

Microsoft has provided two scripts for updating a Windows XP serial number. One for XP with SP1, and one without.

Serial Change script for XP: XPChangeSerial.vbs

Serial Change script for XP w/sp1 or greater: XPChangeSerialSP1.vbs

Simply save the script file to a convient location, and call it from the command line using the new serial number:

XPChangeSerial.vbs xxxxx-xxxxx-xxxxx-xxxxx-xxxxx

You can then check if the serial number has been changed, and is valid by calling this at the command line:

%systemroot%\system32\oobe\msoobe.exe /a

The activation wizard should load and tell you your copy of windows has already been activated.

It pays to have a valid serial number on all of your machines – in more ways than just keeping the BSA happy. It is getting difficult to download anything from Microsoft without a valid serial number.