You don't need to partition the hardrive unless you want to run more than one operating system on the computer.
Just go into the BIOS and set boot priority to the optical drive and insert the windows installation disc. Reboot the computer and then it should say something like "Press any key to boot from CD". Do that and then it will start loading all of the windows installation files then just follow the directions it gives you and you'll be all set.
I think you are mistaking partition with format. During the windows installation you will be required to format your primary hardrive using the NTFS file system but you don't have to do that before you install windows.