Is it possible to "uninstall" windows 10 from a lenovo laptop and reverse it to freedos?

[questionmark23]

So I recently bought a new lenovo 700-15ISK laptop and after installing windows 10 and using it for a short period I decided to return it the display just was unbearable. The shop told me that I have to uninstall windows and Im not really sure how to do it. I think it came with some freedos(when turning the laptop on you had to enter the date month...). How do I go about deleting windows?

 

[okcnaline]

You cannot "uninstall" Windows. You can only download and install FreeDOS, formatting the hard drive with FAT32 over the NTFS with Windows 10.