Do you have Internet Explorer 7 installed?
I had a similar problem just a couple of days ago and it was caused by the
'add-ons' to IE 7.
If you have IE 7 installed, try disabling the add-ons, either one by one to
find the culprit or disable them all and then re-enable when necessary for
certian programmes.
To find the add-ons, click on 'tools' then 'manage add-ons'.
Avi files have a bug in XP. XP thinks that it has to read through every avi
file every time that you open a folder that contains any. You also get the
locked file in use when trying to delete, rename, move, etc. avi files.
The only down side to the above fix is that when you right click an avi file
and select Properties, the Summary page will be blank or grayed out. Which
I decided was a lesser evil than some of the other problems .avi files
cause.
