One of these should help you: * http://support.mozilla.com/en-US/kb/How+to+make+Firefox+the+default+browser * https://support.mozilla.com/en-US/kb/Setting+Firefox+as+the+default+browser+does+not+work * http://kb.mozillazine.org/Setting_Your_Default_Browser#Setting_default_browser_manually -------------------------------- I noticed in your plugins (click "More system details..." next to your original question post) that you have a version of Java with known security issues that needs to be updated. * Next Generation Java Plug-in 1.6.0_21 for Mozilla browsers #'''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 (if needed): http://www.java.com/en/download/faq/remove_olderversions.xml #* Remove multiple Java Console extensions (if needed): http://kb.mozillazine.org/Java#Multiple_Java_Console_extensions #* After the installation, start Firefox and check your version again.