The problem you described seems to be related to some other issues than the OS or the defragger. Maybe you are running an application that locks some files and the defragger cannot handle it? Do you have other apps starting before or while you log on?
Also, did you run a scandisk to check your volumes for defects? I actually don't think that reformatting the hard disk will bring any solution to your problem.
This was first published in June 2002