Build yourself a slipstreamed installation CD by using the I386 folder stored on your computer.

Nlite is a program that can be used to help you build the slipstream disc. Make sure that the license that you have installed is the one that you use.

You can use a program called SIW and under the secrets files it will display the activation key that was used to on that windows installation. Since you use the I386 folder from the same installation then it will work.