If this is happening when using the Maximzie/Minimize button in the upper right corner of the Firefox window, check your settings for the Windows Taskbar; right-click the Windows Start button, choose Properties, on the Taskbar tab, be sure "Keep the taskbar on top of other windows" is checked. If this is happening when using Firefox's Full Screen Mode (F11 is an on/off toggle for Full Screen Mode), that is as designed. See: http://kb.mozillazine.org/Netbooks#Full_screen Otherwise, you may need to try Firefox [http://support.mozilla.com/en-US/kb/Safe+Mode Safe Mode] to determine the cause of the problem. *Safe Mode information: http://support.mozilla.com/en-US/kb/Safe+Mode *Firefox [http://support.mozilla.com/en-US/kb/Safe+Mode Safe Mode] is a diagnostic mode that disables Extensions and some other features of Firefox. If you are using a theme, switch to the DEFAULT theme: Tools > Add-ons > Themes '''<u>before</u>''' starting [http://support.mozilla.com/en-US/kb/Safe+Mode Safe Mode]. When entering [http://support.mozilla.com/en-US/kb/Safe+Mode Safe Mode], do not check any items on the entry window, just click "Continue in Safe Mode". Test to see if the problem you are experiencing is corrected. * If the problem does not occur in [http://support.mozilla.com/en-US/kb/Safe+Mode Safe Mode] then disable all of your Extensions and Plug-ins and then try to find which is causing it by enabling '''<u>one at a time</u>''' until the problem reappears. '''<u>You MUST close and restart Firefox after EACH change</u>''' via File > Restart Firefox (on Mac: Firefox > Quit). You can use "Disable all add-ons" on the Safe mode start window. * See the following for more information ** http://support.mozilla.com/en-US/kb/Troubleshooting+extensions+and+themes ** http://support.mozilla.com/en-US/kb/Troubleshooting+plugins ** http://support.mozilla.com/en-US/kb/Basic+Troubleshooting -------------------------------- <br /> You have a very old version of a plugin installed that has known security issues. * Java Plug-in 1.4.2_03 for Netscape Navigator (DLL Helper) ** You may want to remove the old version of Java before installing the current version, unless you have a use for the old version; see "Removing old versions" below. #'''Check your plugin versions''': http://www.mozilla.com/en-US/plugincheck/ #*'''Note: plugin check page does not have information on all plugin versions''' #'''Update Java:''' #* Download and update instructions: https://support.mozilla.com/en-US/kb/Using+the+Java+plugin+with+Firefox #* Removing old versions: http://www.java.com/en/download/faq/remove_olderversions.xml #* After the installation, start Firefox and check your version again.