Short answer: Read the tutorial!
Long Answer: Seriously, read the tutorial! Those geeks who subscribe to this thread or just come back to read the last posts have noticed how I have criticized some new members who join to post a question which has been answered multiple times, in some cases in just the last post before someone posts the same question again.
I know I should not do that, should not criticize, that I should just answer the same question again and again. That I have also done, my frustration is not and will not be prioritized higher than another member's need for assistance. I just complain because it really is frustrating

.
But in this case now, I hope you don't mind me criticizing a bit and asking why did you not read the tutorial before proceeding? The last part of the tutorial with the title written in really big font is called
Upgrade. It addresses this issue as detailed as possible, explaining step by step what to do and how to proceed.
When dealing with something you are not familiar with, it is never a good idea to read just a part of the tutorial, then decide "Oh I got it!" and stop reading.
An extract from the tutorial, part
Upgrade at the end of it:
When running Sysprep on an upgraded Windows you will get an error message about Sysprep not being able to validate your Windows installation, Sysprep will simply not run. Checking the log file you will find out the reason in plain text:
Code:
Sysprep will not run on an upgraded OS. You can only run Sysprep on a custom (clean) install version of Windows.
I repeat: Please read the tutorial.