Unless you have a blank harddrive or unformatted space on your harddrive, then yes, you will have to create a partition beforehand. Check out the create and format hard disk partitions entry in the control panel to do this. You can right click on the harddrive where you want to install Windows 7, select shrink partition, and then shrink it to leave enough space for your Windows 7 partition, and create the new partition there. Deleting Windows 7 then will only be the a matter of removing the dual boot entry in your startup file, and then formatting the partition where you installed Windows 7.
