The only way that I have been able to remedy this problem is the use of a program located at http://www.free-codecs.com/download/Windows_XP_AVI_Fix.htm
You loose the thumbnail view of avi files when you install this program. Under the Microsoft Knowledge Base they say they have a hotfix for the problem but you must contact Microsoft support by telephone to receive information about the file.
i have a 3.2ghz processor 256mb graphics card nvidia 6200 and 1024 ram memeory
the problem occured when i tried to open an avi movie file, i was moving the avi film from my downloads to shared folder but when i looked in shared folder it wasn't there so iwent back my downloads folder. when i tried to open or delete it a pop-up appearred saying the file was in use by another program, after a while i was able to delete it by dragging it to recycle bin. but 3 days on when i open a folder or firefox or an application
the cpu usage goes from 7% to 100% and pf usage 550mb.