Have you exited out of Firefox and started it back up again since this problem started? Just in case it's a transient glitch.

Preferences

Please check the Tabs section of the Options page. This article should guide you to it:

Startup, home page, tabs, and download settings

In particular, make sure this box is checked:

"Open new windows in a new tab instead"

Any improvement?

i exited out of all my firefox windows, the tabs were closed. when i restarted firefox an update applied. the problem still exists and now is worse. i still get a new window when i click a link. i can get it in a tab if i rightclick first and order the tab but automatically it picks the window despite the setting being open in a tab. now all the tabs that i closed will not reopen. every one i click i get a new window from yahoo. the reload closed tabs only gives me one window from yahoo. i also cannot move a tab from one window to the other. if i try to do so, i get another yahoo window opening in the window i dont want. something has gone terribly wrong with the latest update.

How is Yahoo involved? Do you have the Yahoo Toolbar?

Could you test in Firefox's Safe Mode? In Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

that worked. thank you for your help.

If Safe Mode works normally, it often indicates that the problem you had in regular mode were caused by one or more of your extensions. You can view, disable*, and often remove unwanted or unknown extensions on the Add-ons page. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then cast a critical eye over the list on the right side. All extensions are optional. If in doubt, disable.

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

* In Safe Mode, all extensions are disabled automatically, so the button might be inoperable.

thank you again. the culprit was a new yahoo toolbar and new tab extension. disabled that and things seem back to normal. the reviews posted of this extension are very negative so it seems i am not the only one to have these issues.