This is due to using the old EOL WinXP in which Microsoft does not support with the media feature pack stuff (as they do with Vista and later) as it provided codecs needed for the HTML5 player to be fully used in Firefox and SeaMonkey. Sites like Youtube has not used the Flash Player as a fall back for months now on current videos and many other sites are using a HTML5 player to be more cross platform compared to just using Flash Player Plugin. The Chrome web browser kind of cheats by coming with its own codecs however the version you have is rather old and vulnerable now as Google dropped support of WinXP/Vista back in April 2016. With some workarounds you may be able to use HTML5 player in Firefox/SeaMonkey on WinXP. http://www.msfn.org/board/topic/175591-enable-mp4-h264-aac-html5-video-in-firefox-on-windows-xp-without-flash/ Current is Firefox 52.'''7'''.3 ESR and last major update with be 52.'''9'''.0 ESR out on June 26. This be the last Release to still run on WinXP/Vista and pretty much the last offical browsers to still work. Apart from any third-parties that attempt to back port hack their way in supporting WinXP longer.

thanks a lot, it worked