Why won't my PC start up after the Windows 10 downgrade?

[Windows Central Question]

PC will not start up after Windows 10 downgrade

My new laptop will not start up after downgrading from Windows 10 to 7. I used the downgrade option in 10. It says there is a startup error, tries to fix it automatically, but cannot do so. It can't even start now, and just goes in circles!!

What can I do? 10 was slower and Chrome would not launch from the task bar.....

Thanks.