To throw my two cents worth in. I have defragged leaving things on and turning everything off. It goes faster on my system with everything turned off. I also delete all prefetch files, use Disc Cleanup, etc. to eliminate all files I can before performing a Defrag.
I use Rejzor's Power Defrag first, then I use the Windows Defrag. If I use each alone I end up with a few fragmented files scattered on the disc. When used together usually there are NO fragmented files and NO gaps on the disc. Try it. It makes for a very clean system.
