A: 

You need to reconfigure the QuickTime's files associations in the Control Panel to make it not play the MP3 in your browser.

Of course, you could post a link instead, and have them download the file and then play it - it's more likely to work.

Finally, you could use a Flash-based MP3 player, or re-encode the file and embed it in a Flash that would auto-play it.

scraimer
A: 

I have the same problem as above, but I tried to change QuickTime's files association to make it not play the MP3 in my browser, but I did not success to do it. Would you please do me a favor and give me a more detailed description to do that? Regards,

A: 

Me the same. But I am a campus administrator, and manage a domain. The situation happened When i deployed a Quicktime.msi to all computers, when log in as a normal user, the question mark appears. Only when I log in as a administrator, it will effect and play. Then Everything seems all right! But it will be a exhausting job to set manually one-by-one on these computers. Do you know what causes the problem ?

Looking forward to receiving any valuable suggestion. Thanks!

baker