hi and thanks who can help out

what i want to do is claim back the space from a partation i made for vista i only want to use xp now but now im running out of space i would like to keep the other partitaion for back up software
heres how it looks now
local disc (C:) (My xp drive)
Windows 2000 (d:) planned for back up drive
vista (e:) this is the one i want added on to (C:) to give me more space on xp as i only have 3GB left!
thanks in advance
appoligies to mods if this is in wrong fourm!

P.S does anyone have good recoomundations for back up software?
thanks agian