No doubt on that Winamp is one of the best media player out there on internet.You can play almost all types of video and audios formats on it.
But some users like me love to play only audio files in it and for video they choose other like I choose VLC for video formats.
So problem is that once you install Winamp on your computer it will restore all file formats which it supports with itself, if you change the player form winamp to other then at next start up it will again restore them.
For Eg. If you like to play AVI video on VLC or WMP but Winamp will restore it with itself and force to play in it then next time when you double click any AVI file it will be played in Winamp.
Open Winamp and click Option –> Preference Or just press Ctrl + P, shortcut key,
Now under File Type options uncheck option saying Restore File Association At Winamp Start-Up,