Vista and Xp in drive C


Hi, i have a notebook with windows vista. I want to install windows xp without loose windows vista with a dual boot., i have only one hard disk and i want to make 2 partitions , one for vista and one for xp. but my question is, how can i make that vista and xp run in Drive C? i dont want boot in vista and see "drive c" and boot in xp and see "drive D". i want that always the drive in wich operating system boot was "drive C" .

Thanks and sorry my english xd
Install XP on the first partition and it should consider itself C:. Boot from Vista's DVD outside XP to make an offline install of Vista which well consider itself C: when you are in Vista and something else say D: in XP.
thanks for your answer xd. but i see a little problem.. if i understand you correctly, i must install Xp first and then Vista to make all of them boot in C. right?, the problem is that i have installed Vista and i don't want to deinstall it . it's this the only one way ?
Try using a 3rd party partition manager to hide the Vista partition before you install XP from the XP CD.
Installing an OS from a running system (C:\ already), will make the new install notC:\.
Normally, Installing an OS by booting the installation CD/DVD will make the new OS C:\ (Vista and W7 do), but XP can still install as notC: if it "sees" another Windows partition even when you install it by booting the CD.
You will need to "startup repair" Vista after you install XP because it will overwrite the MBR with the XP version, which cannot boot Vista.