primary partitions

hi..i am having a 200 gb hardisk of which my c drive is having 80 gb.
Now i am planning to install win xp/vista once more in some other partition by which i'll be having a dual boot setup.but i dont want this new os partiton having any connection with the default os partiton,which means i want this new partiton to be a primary partition.how can i achieve this.I hav partion magic with me.