Not totally sure with microsoft! I think you may have limited...

Not totally sure with microsoft! I think you may have limited number of installs then you have to call them (because they may think you are not bona fide)to install again.
The copy of Windows which you rent from them is sensitive to the pc you use so if you change pc there may be problems.
It may be possible to get @an image of your o/s complete with contents by using software called "image for Windows" but whether this solves the issue is not known.
There are Windows savvy posters on HC so they may be able to enlighten you.