XP on 2 Drives..How do I delete 2nd?

I recently got a used computer (hand me down) with 2 internal hard drives. When you boot the PC, it asks you to choose which version of XP you wish to run. Both versions are XP Pro. The C drive is the main and I would like to remove the 2nd occurrance of XP from the F drive. How would I go about this without totally harshing the PC altogether?