If there's no partition on the HDD the installation will create and install on the whole space [ formatting it automatically + 100MB of rescue partition ]. It's better to create your own NTFS partition using tools like parted magic prior to windows installtion and then install windows on any partition you desire.
This way you can even get rid off the 100mb rescue partition that windows creates. BTW, you can create two partitions and install windows on the first one.