this is how yahoo pages appear with my firefox

I clicked "reset firefox" on help~troubleshooting information &this solve the proplem,but anybody knows what was the problem specifically

Hi mamdouh-essawy,

I am also using the latest version of Firefox, which is 16.0.2 on Ubuntu 12.04 but I do not get the same result that you had. It is possible that one of your add-ons are causing this error although it is not limited to this only.

Kindly run Firefox on Safe Mode to see if you still encounter the same page problem. Here's how, Diagnose Firefox issues using Troubleshoot Mode.

You can also one-by-one Disable or remove Add-ons or check if your plugins are up-to-date https://www.mozilla.org/en-US/plugincheck/

If you use extensions (Tools > Add-ons > Extensions) like Adblock Plus or NoScript or Flash Block that can block content then make sure that such extensions aren't blocking content.

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes