There are many website that embedded rich application on any page such movie, short clip or live streaming. Some of them need Windows Media Player to play it. When you access this type of application from your browser, it will tell you that you need to install Windows Media Player plugin to enable to see it. For example if you want to open livetvcenter from your browser, most browsers except Internet Explorer 9 (default can show windows media content) will ask you to install Windows Media Player plugin.
From Firefox if you just click install plugin it will tell you that it doesn’t available so you need to install it manually. If you use Windows 7 you can use wmpfirefoxplugin that you can download free from here. Close your entire browser first and then double click the file to install it and follow all instruction as usual until it finish. Next open livetvcenter website again from Firefox and now you can view the content there.
Windows Media Player plugin for Firefox work for Chrome, Safari and Opera too. Open livetvcenter in your Chrome browser and it will ask your permission to enable this plugin for this time only or always enable for this site. From Safari and Opera, I try to access livetvcenter and both working good with this plugin automatically. Enjoy it!