WINDOW VISTA N WINDOW SERVER 2003

i have window server 2003 on my D drive and window xp on my C drive i now wipe xp and installed window vista on the C drive if i start my system i dont see any option to boo from any of the OS installed vistabootloader and try some things is still not giving option to choose a particular OS it will automatically boot the vista how do i set to give me option to choose from vista or server what will i do now.
2.i want to remove the vista and install my xp on the same partion how is that possible pls