help me, When I check "Always use selected programme to open this type of file" dialog box, new association not works (still use previous association) even choosen application program is valid.

turgay, What is the name of the file extension you're trying to change (.jpg, ,gif, ,exe, ???)? Tufenuf

File extension is mp3. I want to use jet audio but windows still use bs player. This problem is valid also for some video extensions. I thing there is a restriction to change file extensions.

When I changed my .wav and .mp3 files to play with Amovie.ocx thru Rundll32.exe I had to remove several things in the registry to prevent Windows Media Player from being the default player. Sometimes it just won't let go. If you are capable of editing the registry this is where to go [don't forget to back up registry entries first] Hkey_Classes_Root . + mp3file .. + CLSID .. + EditFlags .. + shell ... + open .... - command = ... + play .... - command = You can safely delete CLSID, EditFlags and either Open or Play depending on which one contains the command line for the program you don't want [probably Open] Same deal for anything [most anything that is] that Media Player is the default for like .avi and .mpg files You should try deleting the old association thru the Folder Option first or creating a new action and making that the default association and hopefully placing WMP in second place [multi-association]