I just got windows 7 upgraded on one of my machines to test it out on an actual machine instead of just a virtual machine. This can be a bit different as there are a few things you may not be able to use from a virtual machine. One of the first things I like to check out is the restore options before anything bad happens. Unfortunately Windows 10 can't make a restore drive for whatever reason. Reading the page I ended up at got me to this page for getting your legal windows 7 media. This of course assumes you have your original key with you. I thought I add it here for reference. I have all my media but this will save a lot of headaches as many people can't seem to find their media. In short, it's nice that things are much easier to find so you can get work done.