You should make Windows Recovery Disks in case something happens. When I got my computer, the license is embedded into the software - one computer - one license for whatever Windows OS version on the machine. If all fails, I can get on the Internet to the manufacturer and download Windows OS again from the cloud.
The cloud computing is what is changing everything. Unless you bought a separate version of Windows OS like in a box or something, then computer manufacturers install the OS and it is all there. Actually there is a backup copy of Windows 7 OS also on the computer and then also the OS installed on the computer (both doing something whatever). If something fails then Recovery Disk should fix it (but you have to make probably about 3 DVD's for that) or the manufacturer has a program where you can also make DVD's of the OS incase something happens, or else (if registered with the computer) the manufacturer has the OS that was installed on your machine to download again if needed from the Internet.
The only thing I see with my computer is that the manufacturer uses the same OS for several versions of the computer whether you have certain features (needed for different computer models) or not. It gets on the computer whether you need it or not (probably taking up a little more room).
That is the reality of computers nowadays. If I wanted to upgrade I could but then Microsoft is connected to or the manufacturer and of course to change to a different version of the OS of say Windows 7 or upgrade to Windows 8, there would be the difference in price to what they want for it.
You make your own DVD's to recover or copy the OS system instead of getting a DVD with it on it (at least with my computer.)
PS everything is going to a cloud (mainframe computer that can hold your files or like the OS) and that is what I do not like, but again everyone is going to follow on with it other then Microsoft say for software.