I am having some problems defragmenting my computer.........i set it to defragment, shut off all the programs running (including the screensaver) and when it is done, it doesn't seem that it defragmenting anything. I have a lot of mpeg2 video on my conputer, would that make a difference since the files are so large? I am running Windows 2000

would that make a difference since the files are so large?

Yes, but the more important consideration is how much free space you have. Defragmenting relies on your free space as a "work area" of sorts. In my experience, if you're past 80% capacity on a drive, defragmenting becomes a lot harder. That's not to say that with multiple passes it won't defragment properly, but with such large files, piecing them all together contiguously is going to be difficult without a good chunk of free space to operate with. How full is the drive you're defragging?

I only have around 5 gig available on a 40 gig drive.

Yeah, that's a little tight.

What I usually do, if possible, is move a few files over to another drive until I have 20-30% free. Then I defragment and move the files back. The added bonus is the files you move back and forth usually end up without fragments (since there are generally nice big spaces to put them in after defragmenting.)

Your mileage may vary, of course.