Why does defrag Fail?

I really want a tech to help near this. I asked once and got no clad answer. Anyways, the previous question was( and I am editing and count bits):

I run defrag with an /f switch,as very well as with /r switch, and also lacking the switch ; I also run it from the command prompt. Its not the "Neat Freak" in me, since I know that a 0,0,0 defrag convenience set is possible ( the majority of the machines I do achieve that); its the one that fall short that have me stumped. There is a set of nouns like chkntfs or similar, and the command allows defrag to run fine. These extra command appear to unlock some drives.Also, some hardware settings can raison d`¨otre the failure, I only can't figure out how to find which is which.

Totally stumped... I own tried so many permutations. I enjoy been working on several hundred computers over the finishing few months, and I need to obtain as much info as possible. Almost all of the PCs are running XP Pro SP2. I really requirement an answer from someone with a network PC world...

Why does defrag Fail?

you might have easier said than done drive problem or you use you computer when you run Dfragment
It may be failing due to the lack of available disk space. Windows XP prefers to own atleast 15% disk space available to properly defrag I believe.
The cause for this could be another program explicitly running simultaneously. Try closing all other programs, and later defragment.
I used to have problems beside defrag. It would get to in the order of 10 percent and stop everytime.

A while back on some request for information site (not this one), someone told me to restart the computer and hit F8 during startup. Then select safe mode. Defrag from near. Well, I tried it and it worked fine.
see property for sale