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I've seen some fairly involved sites with methods to try this, don't have the links.
This is not easy to do.
Maybe someone will have a link to a way to do this.
Most people use a Backup and Restore Image program. They are easy to use and reliable,
you can backup right after installation and/or weekly and get back your OS with all programs installed and the OS activated in about 15 minutes.
Here are a couple free proven programs. Macrium Reflect Paragon Backup & Recovery 10 Free Edition
A long list of free programs that will work With Windows 7. FREE Great Programs for Window 7