QUICK Reformatting Question

So I'm in the middle of reformatting on another computer, and after selecting what drive and it says there's already an OS installed, is it okay if I continue? I just wanna make sure.

~THANKS! -In advance.

If you already did a back up of your important files on that OS and don't need that OS anymore, yes you can format. Btw you should choose the long format option, not the quick one.