every few weeks i like to erase the freespace on my HD. 1st i clean out all the junk, basically all of my temp folders. the next part is where i get confused, because i've heard several recomendations that contradict themselves. this part consists of 3 things.....defrag, scandisk, and erasing free space. could someone tell me what order i should do these in, and most importantly WHY? i really want to understand the reasoning behind this.