said by Wai_Wai :

Use these music players instead.
Windows Media Player + QuickTime Player + RealPlayer may add too many unnecessary features, add a lot of things to your system, and make them bulky, and so on...

Or if you hate intalling a lot of media player just for the sake of opening their related file associations...

Use the much lighter ones all-in-one media player (for free! :P):
The music player (light and simple), it can replace Windows Media Player:
»www.free-codecs.com/download/Med···ssic.htm

To replace QuickTime, add this plug-in:
»www.free-codecs.com/download/Qui···tive.htm

To replace RealPlayer, add this plug-in:
»www.free-codecs.com/download/Rea···tive.htm

Note: You may experience some minor problems when opening some of RealPayer or QuickTime files. If it was the case, close and re-open the music player and open the files should work again.