K, thanks a lot.
So labels, which are in fact much easier to change (I always forget where the letters are managed from), are always absolutely reliable in every systems environment?
Good, second question: I read that boot.ini, responsible for the booting of every NT-based multi boot system, is always located on "C:\", which means that formatting this partition dooms the entire multi boot system. If C is no magical letter which keeps the world together, then I would like to inquire what determines which partition will carry this duty. I also read that Vista and Win7 booting works differently, but I assume there's a key boot.ini-esque file there too. So which one is it and where can it be found?
I'm sure I'll grow tired of one of the systems sooner or later, so I would like to avoid losing them all with the formatting of one partition.