Defragmenter could not start xp sp2

I have worked on SEVERAL computers where after I load SP2 for the customer which is part of what I do before I give a computer back, all the updates; the defrag gets screwed up.

I was wondering if anyone has figured out the resolution to this yet.

I have heard it can be due to NAV but I dont know if that is true yet.

People have said run sfc, that doesnt fix a thing.

I have tried running the inf to install it again, copying and extracting the files from computers where it does work, STILL NOTHING.

I have also tried using regmon and filemon and they dont seem to show any errors with the defrag.

Any one?

so what exactly happens when you try running it? any errors? or does it just not start?