Try uninstalling 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.

Removing the Ask toolbar did not fix the problem for me.

I am running Windows 7 and received an update on 5/2/2012 at around 8PM and spent close to an hour try to get Firefox to work like it did before this latest update.

I click on new tab and get a new window instead.

Any other ideas? I hate IE, Chrome, and Safari, but I'm being forced to use one of them to work online. I need tabs!

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

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