Does NT disks get fragmented? Yes. Yes. YYYYYYEEEEEEEEEESSSSSSSSS. I have seen NT workstations with disks so fragmented that it was impossible to install another application. Its one of the first things I check if NT starts gets flaky. I recommend purchasing Diskeeper and using it to schedule daily cleanups. You can download a freeware Diskeeper Light which you can manually run. Its better than nothing, in fact, its what Microsoft purchased for NT 2000 (essentially). Buy the full-version and schedule daily defrags of you disks, its worth it.

For the novice, if a large file is copied to your disk, if there is not a single spot on the drive large enough for the file, what happens is that the file is cut into pieces and stored wherever there are free spaces. When the file needs to be used later, the operating system has find and to read all those separate pieces. As you can image, this makes the disk seem much slower than it really is.