OK first are you planning on reinstalling you operating system (OS) or is that installed on another drive? If you are not reinstalling your OS then from windows (assuming you are running windows operating system) click start (the windows icon in bottom left corner) then left click computer. Right click on the drive you wish to format then click the format option in the list. You will then either do a quick format (leave ticked) or full format (untick). This will wipe everything from the drive so make sure you back up anything you plan on keeping on another drive. Repeat above steps for other drives that DO NOT have your operating system installed.
EDIT Formatting one drive will not affect any others.
If you are reinstalling your OS then you will need your OS DVD/CD inserted set your PC in bios to boot from the DVD/CD drive first then boot your PC. You will have the option from the installation disc to Format any drives on your machine.
NOTE!!!!!! If you format any Drive on your machine then all the data on that drive will be deleted!!!