Uninstall the Ask toolbar and it should work again. There is a compatibility issue with the Ask toolbar and Firefox that prevents new tabs from being opened.

Strange you would talk about Ask. I do not like Ask and had removed it from the toolbar when I was fiddling around with the problem. The Ask toolbar was gone, even in the search engine bar. Restarts were used. If you have no additional bits of advice, I think I will go to an older firefox. If not then windows vista is next to go.

There Ask toolbar may still be installed, your user agent string includes "AskTbBLT/3.11.3.15590" which is added by the Ask toolbar. Check the Windows control panel add/remove programs, and the Firefox add-ons manager to see if either show the Ask toolbar.

http://kb.mozillazine.org/Uninstalling_toolbars

Here is the answer to the problem. Remember I am using Windows Vista. First I went to my firewall in Spyhunter 4. I opened the System Guards and removed the older version of firefox.exe. I then clicked on Mozilla Firefox in (Safe Mode). Before it opened, it allowed me to reset the tool bars and Applications. I closed the Mozilla Firefox (Safe Mode). I then open Firefox in regular Mode and I was able to activate the Open New Tab and use the Ctrl - T.