DVD that came with mobo

What exactly do I need the dvd that came with my mobo for, do I use it after I install the OS?

Put that DVD in a nice safe place. Don't get rid of it. They contain the chipset drivers, etc., for your motherboard set-up.

Ok so I don't need to use it when I install my OS? I know this is off topic but what are those 5.25 inch drive that reads the temperature and other stuff inside the pc?