Tl;dr: I have three operating systems on my computer, two of which are corrupt and I don't want there. How do I get rid of them?
I recently bought a PC with windows on it and installed Linux OpenSuse Leap 42.2 on it. I thought I had deleted all the Windows partitions in the process, but when I boot the computer, it still gives me an option of booting Windows. Fast forward a few days, I mess with the grub file in the new operating system so that it won't boot and end up installing Leap again. Now I have three boot options: Windows, my corrupt Leap 42.2, and the new Leap 42.2. I want to get rid of Windows and the first Leap I installed. How do I do it?