I think that chronei is doing a dual boot installation to add Linux Mint to an existing Windows machine, and has obviously got to the totally unhelpful setup page where you have the slider control to select how much of the hard drive to use for Linux Mint.
This is a very basic problem, and a piece of very poor design or a bug. As chronei says, even the documentation doesn't help. There is no information as to which side is which!
So, for chronei and anyone else in this situation, my experience when installing Linux Mint 13 Maya alongside Windows XP was that the right-hand side of the slider control is the amount to be taken up by linux, and the left hand side is kept by the existing Windows system.
HTH, and good luck,