This may be your issue. Ran into this once myself:
Explorer hangs with Watson crash when opening folder with many AVI files
There appears to be a problem with Windows XP SP2 affecting most ppl and its stability when selecting AVI files done in divx or xvid format (MPEG's are fine)
Opening a folder containing a large number of AVI file can open quite slowly because the OS has to open each AVI file and extract info from AVIs. If you have a large collection, you can speedup XP's folder access to blocking it from automatically extracting this info.
Rename the key by placing a minus in front of the keyname to enhance file system speed when working with AVIs. You will need to open "regedit" . Start - Run - regedit.
find and modify :
HKEY_CLASSES_ROOT\ CLSID\ {87D62D94-71B3-4b9a-9489-5FE6850DC73E}
to
-{87D62D94-71B3-4b9a-9489-5FE6850DC73E}.
If it causes problems, just remove the minus again.
----------------------------------------------------------
ALTERNATE FIX:
This happens when the files have been encoded with the DivX codec which
came out after XP. DivX now have a new version of it that does not
generate the 'bad' information that crashes explorer when it goes
looking into the files when you open a folder, to look for the extra
info about Properties - like resolution, frame rate, etc. But old files
will probably still do so (and the explorer in SP2 is more badly
affected than before)
It may be best to do without the extra property info - Start - run -
regedit.exe, open to
HKEY_CLASSES_ROOT\SystemFileAssociations\.avi\shellex\PropertyHandler
highlight that and delete it
