Installing windows on a partition

Hey guys, I'm going to be removing my laptop hard drive and placing it in my desktop. I plan to create a partition on the drive and install windows to that and then move all my files from the other partition. I will be installing using an external hard drive. Is this possible or will I have to format my entire drive to install windows? I'm going to be installing windows 7 if that matters. 

Yeah you can easily do that with Disk Management or some other alternative.