My roommat has very little free space on his hard drive, and hasn't defragged in a while. He wants to do it, but it says that it needs 15% free space on that drive to do it effectively. But it asks if you want to do it anyway. I told him to hit no, because I didn't know if it made a huge problem. Any thoughts are appreciated. If anything else is needed feel free to ask, as I will post back.