What kind of videos? All kinds, or only Flash or Quicktime or Real Media, or what? Does that happen in Firefox safe mode?

• http://kb.mozillazine.org/Safe_mode

i just tried safe mode and that makes no difference. the videos that do not load are ones embedded in websites such as the huffingtonpost etc. the website loads as normal. when i click on an article with a video the article appears but the area where the video usually appears is just a black box. typically that box contains a "promo shot" and video operating controls. recently this area is just black. this happens on numerous news type websites. when i use safari as my browser everything works fine

Try to update Flash to the latest version.

• https://support.mozilla.org/kb/Managing+the+Flash+plugin

• http://www.adobe.com/software/flash/about/
• http://helpx.adobe.com/flash-player.html

that seems to have solved the problem many thanks

You're welcome