When you install Windows, it will write itself to the Master Boot Record (MBR) and will delete anything in it's path. That doesn't mean it will delete your partitions, it will just delete the mbr record. Whereas when you install a linux based bootloader such as Grub or Lilo, it will create a menu for you to choose which OS to load. My advice would be to load up a livecd of some sort, Ubuntu or whatever, then just use fdisk(or cfdisk) to create your partitions. Then you can go ahead and install linux or windows. however, if you do windows last, you'll have to boot up your linux livecd again, and fix the mbr. If your using grub, you'll have to read the manpage, cause it defines partitions a little differently from fdisk. Your partitions will still be there though, regardless of which app you use to create em. Hope this helps, I'm not very good at answering questions.