How to uninstall a preinstalled Windows 10?

I got a Lenovo which had Windows 10 before I bought it, I've tried solutions that help computers that installed Windows 10 before Windows 8, but it doesn't work. Is there a way to uninstall a preinstalled Windows 10?

You can, but I would just keep W10. Trying to go back to an older version might not be worth it. You have to buy Windows, which can cost about $50+, and then you have to look for drivers. If you can't find the appropriate drivers, then you're out of luck.