i have 10.5.1 with vista bootloader (running xp and osx 10.5.1) if i install 10.5.2 will it overwrite my bootloader?

second question, if i disconnect first boot disk (windows), install leopard in second disk , when its installed. connect again first disk (windows) and fix vista bootloader to redirect to leopard disk (as i have now with 10.5.1 , will it boot ok (efi, etc) or will it give me problems.

i ask this because im new to efi, and i dont know if it will load ok like this (windows bootloader -> efi -> leopard) or its something like (efi -> whatever bootloader > leopard, and if its the case because of efi my windows partition will begin to do strange things)

help appreciated.

// i dont know where i put my linux distro with the program to fix mbr....and i dont want to screw it again.
// sorry for my languaje, im from another planet.