Computer Help and Support

Reformat the disk and install it.

Assuming you still can get W10 from them. If not, lot's of places I'd imagine still host W10 install files you can download.

There's a few things you have to look out for like making sure you either have the license key for your windows copy (like on a sticker on the lappie, or somewhere in the box), or you set up a Microsoft account that tracks the license for that machine.

And then there's the fact you may have files you 'care about', you'll need to back them up before you reformat the drive.

And a few other concerns.

Myself, I'd never use the copy of Windows that came pre-installed on a new machine. Too much crap on those vendor-modified OS's.

MHO, YMMV.