I have heard that a disk can become so fragmented that it is beyond the
capacities of some defraggers. I don't know if that's true, but one thing
to try if you have run out of patience with the native defragger is go to
www.raxco.com and download PerfectDisk Pro, free as a trial. It has the
best reputation for succeeding with hard to defragment disks. Once you
clean up the extreme defragmentation, if that's the situation, then maybe
the native defragger will be able to carry forward from week to week.
srdiamond