What I would do is remove the Hard Drive, put it in an enclosure and attach it to a computer. I would then erase the Hard Drive on that computer and put the Hard Drive back into your laptop and re-install the primary OS (e.g. Windows) using bootable USB.
[http://go.microsoft.com/fwlink/p/?LinkId=616447|Windows Media Creation Tool for creating a bootable USB]
Unfortunately I could not find a guide for removing the Hard drive for your computer. Maybe someone else can help find one?