Try control alt delete, check and see if stimon is running. If so click "end
task." If that doesn't do it continue ending programs running until defrag goes
all the way. You only need a few running. I know explorer is one, but don't
worry if you click on one that should be running. nothing will be harmed
Also I used to shut down the screensaver by clicking on none until dfrag was
over. Not sure if that helped or not, but it didn't hurt.