did you know that every time you use open with... with unknown files explorer stores the extension of that unknown file to the registry just to preserve the information which programs to group as recommended.you gotta agree,this is stupid.the cure is sendto menu.sendto menu is actually a superhidden folder usually at c:/documents and settings/YOURUSERNAMEHERE/sendto.type this into run box (replacing YOURUSER.. with your actual username) and in window appeared choose new-shortcut.browse for the application you frequently use for openin files.create a shortcut to it.recommender are notepad,your archiver,your audio/video player,your web browser... never use open with again! there is a way of removing openwith context menu entry from the registry.i ll post that soon.if set properly sendto will be way more powerfull than open with