anniebach There is an option for Windows 10 to run looking as though it is Windows 7. You are unaware of it being any different, but you get all the advantages of Windows 10.
W10 takes a long time to download and install, which is why people think that their computer has seized up, when it is still busy and won't respond. The best thing is to start downloading and then go out for the day, or begin at bedtime and just let it get on with it overnight.
I had a fright the first time I tried to use mine next morning after downloading. It invited me to restart, but I thought I could postpone that and declined. Then I found it wouldn't let me do anything at all. Apparently, to download updates and download the new system, Windows has to create a new user login for itself, because it is not the normal user doing it. So when it has finished, the new user is still logged in and no-one else gets a look-in until the machine has been restarted and the normal user logged in.
You do have to go through all the settings to make sure it is doing things as YOU want, and not at the defaults, but it does take you through the process if you follow instructions.
A few of my applications don't work with Windows 10, but all the common ones do. My emails and addresses are all still there, and so are my documents and internet links and passwords.