If you want to do it the hard way open the registry.

Check these keys and make sure the default is the Windows Media Player.

HKEY_CLASSES_ROOT\ .mp3 - default value and Content Type
HKEY_CLASSES_ROOT\ WMP11.AssocFile.MP3\shell - default value
HKEY_CLASSES_ROOT\ WMP11.AssocFile.MP3\shell\play\command - default value
HKEY_CLASSES_ROOT\ MIME\Database\Content Type\audio/mpeg - CLSID and
Extension

For me it was Nero Showtime that had stolen the "default" even though in
Default Programs, Windows Media player WAS the default and it was the program
that opened.



"Gabriel Lozano-Moran" wrote:

> When I click a .MP3 file or an .MPG file from a web site it opens Windows
> Media Player on Windows XP. On Windows Vista I get the following error:
>
> Internet Explorer cannot display the webpage
>
> Most likely causes:
> You are not connected to the Internet.
> The website is encountering problems.
> There might be a typing error in the address.
>
> What you can try:
> Diagnose Connection Problems
>
> More information
>
> This problem can be caused by a variety of issues, including:
>
> Internet connectivity has been lost.
> The website is temporarily unavailable.
> The Domain Name Server (DNS) is not reachable.
> The Domain Name Server (DNS) does not have a listing for the website's
> domain.
> If this is an HTTPS (secure) address, click Tools, click Internet Options,
> click Advanced, and check to be sure the SSL and TLS protocols are enabled
> under the security section.
>
> For offline users
>
> You can still view subscribed feeds and some recently viewed webpages.
> To view subscribed feeds
>
> Click the Favorites Center button , click Feeds, and then click the feed you
> want to view.
>
> To view recently visited webpages (might not work on all pages)
>
> Click Tools , and then click Work Offline.
> Click the Favorites Center button , click History, and then click the page
> you want to view.
>
>
> This only happens with types that are linked with Windows Media Player, I
> believe this is a security settings of some kind. I have disable OneCare
> Live's firewall and anti virus to see if that was causing it. Does this ring
> a bell and how to solve this?
>
> Thanks
>
> Gabriel
>