See How to set the home page

Also, go to Windows Control Panel | Java | Update and click the Update Now button. The version you're running now exposes your system to attack.

After you update, go to Tools | Add-ons | Plugins and you'll see v1.6.0_24 in the list. I've included a screenshot here for you so that you know what to look for. Disable all the other Java plugins you see in there except the two shown in the screenshot.

Thanks for your help, but it didn't work. I tried and disabled the other plug-ins but firefox still does not open my Yahoo home page. I even put back the firefox 3.6 and now that doesn't do it either. This is crazy.........

Please do the following.

Press CTRL+SHIFT+DEL, change the setting at the top to Everything and then in the menu below, checkmark "Cache" (uncheck all the others). Then click the "Clear Now" button.

Next go to Tools | Options | Advanced | Network (tab) and in the Offline Storage menu, click the "Clear Now" button.

In the Tools | Options | Advanced | General (tab) menu, uncheck "Tell websites I do not want to be tracked" if it's enabled.

Next, go to Tools | Options | Privacy and then click the "Show Cookies" button. Then delete all the Yahoo cookies.

Finally, go to File | Exit and then restart Firefox again.