PixelAttack

Hey guys, I just installed Vista onto my PC but the XP operating system is still there :eek: Usually when you install a new OS it give you the option to delete the old one but this time, it did not. I don't think it can be done through the setup disk Does anyone know what I need to do? XP has to go, its taking up all the room! (when I boot the machine, it lets me chose between the 2)