"Name this file" mystery file won't defrag

[George]

Am running two PC's, both fairly new, WinXP professional, with plenty of RAM
and drive space. When running defrag, one keeps saying at end... "Some
files on this volume could not be defragmented". I'd really like to fix
this. In the View Report at end, only material difference I can see is...

FOR PC#1 THAT WORKS GOOD:
File Fragmentation
Total fragmented files =0
Total fragmented files =0

FOR PC#2 THAT WON'T FULLY DEFRAG:
File Fragmentation
Total fragmented files =1
Total excess fragments =16

PC#2 does have a lot of games on it. And PC#2 View Report won't tell me
which file won't defrag...that is, it's name. So how can we close in on
what program is causing this (might not even need it, might can uninstall
it, might be a leftover temp/installation file)

Not really looking for third party software or other kinds of ways... I'd
think we could correct this somehow with some diligence and plain Windows,
would greatly appreciate suggestions.

Thanks,
George

 

[George]

(correction, this paragraph should instead read...)

FOR PC#1 THAT WORKS GOOD:
File Fragmentation
Total fragmented files =0
Total excess files =0