I have been using Clonezilla for over a year to clone various Dell Optiplex model PCs, with great success. Until now. Nothing has changed in my cloning process other than the PC model - Dell Optiplex 755. The cloning process that I have used is as follows: I've created a "golden" PC", then I ran sysprep.exe to "seal" the PC. Next I ran Clonezilla, using the default selections, from a CD in the "golden" PC. The clone image was saved to a flash drive. Then I used clonezilla to restore of the image onto a different PC (same model and hardware) and this ran correctly. After which, the cloned PC was powered on and the Microsoft Windows XP Pro set up started. When prompted, I entered the Windows Product Key that is on the label on the PC. I was informed that the key was invalid. Yes, the key was entered correctly. Yes, the key is a valid and a legal key. I have yet to call Microsoft about this. Any help is appreciated. Thanks.