Do I need a C: drive?

I have installed Windows 7 on my pc and still have a copy of XP to which I can dual boot. Windows 7 seems so stable though that I probably won’t use XP again. It resides on a small C: partition on the smallest of my three internal hard drives. I’ve put Windows7 on one of the other drives I: The thing is I don’t really need this smaller hard drive. Can I remove it completely and do without a C: drive or is there something with Windows that requires a C: drive?