Since you forgot to tell what recommendations from what sites you followed, it's impossible to comment on what you did. Some are to the point, many others are useless.

If you don't have a recent backup to go back to (why not?), reset your PC per Microsofts instructions in http://windows.microsoft.com/en-us/windows-10/windows-10-recovery-options.
If that fails, it might be a hardware issue; then going back to Windows 7 won't help.

Kees