This is purely a shot in the dark, not knowing what the problem is, but defraging is not enough to keep your system running well. If you surf the net and work with large file sizes as we typically do when working with graphics, you end up with a lot of junk files and a corrupted registry. I use a product called System Mechanic that was recommended to me by the pros that built my custom system. I run it about once a week or so and defrag roughly once a week. It keeps my system in top notch shape. Its amazing how much drive space can be consumed in a relative short amount of time with junk files. These junk files take up space on your hard drive that is needed for virtual memory.