Thanks for the fast answer... The only process found is explorer.exe. I don't think it's realy used by another prog or something, it's just a windows xp bug and what is annoying me is that I had the fix.
I have one .avi movie that I cannot erase, move or rename... (It is being used by another person or program) I had this trouble a while ago and I think there's a command or a file to delete to correc that, I'm not sure... Thanx for your help.