I took out WMP and WMP 6.4. Then I used this. [Version] Signature=$CHICAGO$ [DefaultInstall] AddReg=Reg.Settings [Reg.Settings] HKCR,.mp3 HKCR,mp3file,,,"MPEG Layer 3 Audio" HKCR,mp3file\DefaultIcon,,,"C:\Program Files\K-Lite Codec Pack\codecs.ico" HKCR,mp3file\shell,,,"open" HKCR,mp3file\shell\open HKCR,mp3file\shell\open\command,,,"""C:\Program Files\K-Lite Codec Pack\Media Player Classic\mplayerc.exe"" ""%L""" HKCU,%SMWCEF%\.mp3,Progid,,"mp3file" HKCR,.wav HKCR,wavfile,,,"WAV File" HKCR,wavfile\DefaultIcon,,,"C:\Program Files\K-Lite Codec Pack\codecs.ico" HKCR,wavfile\shell,,,"open" HKCR,wavfile\shell\open HKCR,wavfile\shell\open\command,,,"""C:\Program Files\K-Lite Codec Pack\Media Player Classic\mplayerc.exe"" ""%L""" HKCU,%SMWCEF%\.wav,Progid,,"wavfile" [strings] SMWCEF="Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts" The wave files play with classic, but the mp3's don't. Also how do I get this extensions to show up in my computer, tools, folder options, file types?