When Microsoft released Windows 10, they allowed you to install and use it for up to 30 days and if you did not like it you could revert to your previous(Win7 or Win8.1) operating system. Within the Windows 10 install software was a file that would wipe your previous Windows OS from our hard dive. You can try finding Windows 7 online and take your chances or reinstall from the recovery media you made before installing Windows 10. If you didn't think it necessary to create recovery media or to backup everything you are sure wishing you had.
The first thing I do when buying a new computer is create recovery media to use when needed. If you drop the laptop or kick the desktop or have hard drive failure in any computer your recovery media has your OS and original software titles to install in a new hard drive and you can get most of your files,photos,videos, documents and whatever else from your backups.
Good Luck and remember Microsoft is NOT your friend.
If it is under 30 days old it is easily doable if longer good luck.Or so I was told. You may wish to take it to a computer repair place if you are not good with computers otherwise google your brand and model and how to delete windows ten and revert back to windows 7
If you have recovery then you can go back to the previous version of windows stored on your hard disk
Buy a Win 7 disc.
you gotta buy windows 7 then
Go to settings, find recovery, then click Get started when you see "Go Back to an earlier build" that should work.
Too bad is what Microsoft said