I will show the method that I use to do to backup windows 10 activation

before I do the clean install of my windows 10 in the case that

you lost your activation after do the clean install.

Btw, If you do the clean install and your windows already active you don't need to restore this

Test working with Windows 10 Pro 32 Bits

First download this program ( It's FREE ) : Opa Backup OPA-Backup - Office-Produktaktivierung sichern und wiederherstellen

After that open the program opabackup342 (I recommend run the program with admin right )

It's not has windows 10 but this will work with windows 10 too

Make the back up ( you can save backup anywhere but Please select the back up location that not in the drive you want to install windows, because after you do the clean install that drive will wipe all data isn't it ? XD )

Back up finished

Back up files

Warning !

please disable internet connection before do the restore the backup.

restart the computer after finished restore

- There are significant hardware differences between the computer used
for backing up and the computer used for restoring.

- The version of Windows on the computer used for backing up differs
from the computer used for restoring (e.g. when upgrading from
Windows XP to 7orfromWindows8.0 to 8.1).