I will follow these steps to get W10 Pro 1151 ISO directly from MS site.
Go this page using IE11, hit F12 and change user agent string to Apple Safari(ipad) found in the emulation tab, and boom you can download the 1151 ISO without needing MS useless and slow upgrade agent.
https://www.microsoft.com/en-us/software-download/windows10
Create bootable USB stick with Rufus portable exe.
https://rufus.akeo.ie/downloads/rufus-2.6p.exe
If you have W7/8 pro key from your old lap/desktop, then follow these steps to activate using your old keys.
http://www.zdnet.com/article/going-pro-how-to-upgrade-windows-10-home-without-hassles/
Once activated, MS will store your system specs in their server and you can always activate it should you need to reinstall your Windows.
And you can now clean install from your USB3 stick anytime, like the old days, but much faster.