.asx and Firefox

I have a online radio station that plays Elvis, url is http://n90.mediamaster.com/myradio/Elvis24Seven.asx. I set it up as one of my home page tabs on my home computer and my laptop. On both, I use Firefox. On the home computer, the page opens within Firefox without launching Windows media Player. On the laptop, it launches the WMP. I prefer the smoooth operation of playing within the page. I cannot figure out the difference in tools/options or otherwise that is the difference between the 2. Any ideas appreciated.