You have multiple ways to do the disk formatting.
1. Windows Bootable Disk : You can download utility such as WiNToBootic to create a windows bootable CD or DVD. All you need is new CD or DVD. And utility like WiNToBootic to extract it's content onto the DVD or CD. After that you can boot from the CD and format the drive where you have Windows 8 or any other Windows installed.
2. Windows Installation Media : This could be Windows official CD or DVD that contains operating system installer. You can boot from the CD or DVD like this from BIOS. And here you can format the drive before installing anything. Such installers also allow you to use Windows Disk features. That means you can use the command prompt from it's menu and format the drive.
3. Bootable USB This installation media can be used to boot into the installer menu options and disk tools. All you need to do is create bootable USB that contains windows installer or simply allows you to run disk tools. This type of USB can be created from any windows computer and you have to format and install such tools on the USB drive.
4. External computer : Take your hard disk to another computer and attach it as a slave. And this way that computers Windows will recognize this HDD. And you can view the new HDD from the disk management tools. Here you can format the external HDD and set the file system type as well. This is the easiest way but requires you to remove the hard disk of your computer and attach it to another. So unless you know how to do that it's not easy for most people.
These are some of the methods that should work to get your HDD formatted regardless of the type of operating system it has already within itself.