I suppose while we're talking about this we should mention that it's best to pick a defragger and then stick with it within reason; i.e., don't run PerfectDisk today, then MS next week, then PerfectDisk, etc. You'll just constantly be scooting your files around.
I loaded up PerfectDisk yesterday and I'm pretty pleased with it. Only "buy nag" I've seen so far - and it's not really one so much - is its startup window. Might be able to disable it, haven't really checked. At any rate it's very reasonable.
I like the way it does its boot defrag - it does put up a basic screen to let you know what's going on. Much better than sitting and wondering. Thanks for the tip on how do initiate that Leo, I agree that it's not particularly obvious. Personally I too see some value in defragging system files, and file placement too for that matter.
Nice catch, thanks again.