Just to add to what has been said here: if you do as Hogfly has suggested, upon installation of Red Hat and all the desired applications you are installing with it, when you boot your PC, you'll be given the Grub boot loader menu. From here, you can choose which OS you would like to boot to. But as Hogfly said, you have to label that Windows partition during your install because if not, when you go to boot your PC, it'll appear (according to the boot loader), that you only have the Linux partition installed.