Issues with a black (empty) toolbar can be caused by a plugin or an extension that is not compatible with Firefox 3.6 and isn't working properly anymore. A toolbar like the "ZoneAlarm Spy Blocker Plugin Stub for 32-bit Windows" and other toolbars like "Ask.com" or "My Web Search" can cause this issue. See http://kb.mozillazine.org/Issues_related_to_plugins#Identifying_installed_plugins See also View > Toolbars