hey not sure if you are still having issues with this but it may be caused by a firefox add on..you should go to your programs and there you should look for the a program called 'myfreeze' and delete it. your web browser should be good after that.

hope this helps :)

Thank you very much Deb. That did it now I can use "new tab" without Yahoo search page appearing. Dona

AVG is the culprit (if you're using that particular anti-virus software). Disable the AVG toolbar in the program's advanced settings, and the Yahoo search bar miraculously disappears, too...

Under the Firefox Tools drop-down > select Options > under the General Tab > select Manage Add-ons > click on extensions > scroll down to "Freeze.com NetAssistant v. ??? > disable Freeze.com NetAssistant.

This worked for my Firefox v. 4.0.??