How to change default video playback?

If it is a file on the hard drive, right-click it and select Properties.
Under the General tab near the top is the Type of file and just below
that is Opens with:.  That shows the file association and it can be changed
by by selecting the Change button.

 

If it is a CD, right-click the drive in My Computer and select Properties.
Select the AutoPlay tab.  In here you can select content types and the action
you want Windows to do.

Hi, skybird, thanks.  This one is Nero Showtime, so it's a bit tricky -- it's an application inside the Nero Smartstart icon.  I tried this numerous different ways and can't find any way when clicking through to "Properties" to get a screen that says "Opens with".

Since I can't figure out how to turn Nero off per se, is there some other way I can set WMP as my default in all video and audio playing?  I noticed that Nero is having an especially adverse influence on my listening to radio stations online, which I prefer to do with WMP -- Nero tries to open the streaming audio, fails, and that is that!  :smileyvery-happy:

 

Ideas?  Thanks.