I installed 10, seemed great at first, several good features not on 7
A couple days later, it the same as crashed, black screens everywhere, w/ an alarm sounding that could not be turned off. The reason given was that my pc contained malware/spyware that win 10 will not tolerate.
After messing w/ it for a while, I was able to get to the page that lets you change back to 7, but only after you answer questions why you are changing back.
Thru is all, I gather that MS is just experimenting w/ 10, and fix the problems as they come in.
At any rate, the change back to 7, was simple, and took only about 20 minutes, much faster than the change to 10.
And my pc is working quite well, and faster now, despite have spyware/malware problems ??