Hey 60 - when I was first getting into computer work in the early 80's - defragmenting the files on the hard drives (school minicomputer) WOULD really help. And it would help some on the early PCs that came later.
But in todays world, with any recent type of hard drive/PC (anything less than 5-10 years old), it is a very rare case to be able to see ANY difference whatsoever.
The smarter drive controller electronics, the speed of the drives themselves, multiple read heads, etc, etc, have made delays from file fragmentation non-existent.
Plus, a lot of people have the notion that defragging somehow affects the registry, cleans up old programs, fights viruses, etc... But all it does is reorganize file layouts to be less "fragmented".