When I try to view a video, Real Player doesn't start, but some other video player starts?

What is happening is that Real Player is no longer the default player. This may vary with older versions of the Real Player, but with the current version of Real Player click on VIEW, PREFERENCES, UPGRADE, MEDIA TYPES, AUTO RESTORE SETTINGS.... Make sure the following are checked:
-SMIL document
-RealAudio clip
-RealMedia file