Most software needs to be installed on the same partition as Windows.
Your personal files (Documents, Music, etc.) are easily moved to a different partition, which is a good thing to do, as long as the partition is on an internal hard drive. This is easily done through the Location tab. The thing to remember is that you don't only want to move those files to the new partition ... you want the new partition to be the default location for saving new files. I'll gladly show you how it's done.