Dumb question but where is my windows?!

[3t3P]

What I mean is. I originally had a student copy of windows 7 64bit Home premium (I think!) which was a physical CD-ROM.

I then upgraded for free to windows 10.

When I want to format or upgrade/change my PC, how do I now go about this?!

Do I pull the files for windows off my PC before upgrading or use a serial key or what?!

Thanks

 

[3t3P]

But how do I even put an OS on a formatted/new system?!

Would I install my old win 7 first and go from there?

I miss CDs