Firefox 3.6+ versions have a feature to allow the user to hide the Menu bar.

Hit the Alt key to temporarily show the Menu bar, then open View > Toolbars and select Menu bar, so it has a check-mark.

See also Restore the Menu bar in Firefox

Your above posted system details show outdated plugin(s) with known security and stability risks.

• Java Plug-in 1.6.0 for Netscape Navigator (DLL Helper)

Update the Java plugin to the latest version.

• http://java.sun.com/javase/downloads/index.jsp (Java Platform: Download JRE)

Update the Adobe Reader plugin to the latest version.

• http://get.adobe.com/reader/otherversions/

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Thanks, this worked. An easy fix!

This is why I will never use firefox as a default browser. I am not computer illiterate, but I just wasted 15 minutes looking for an add on that I know I installed. Being able to hide a toolbar when hitting a key, then not having any menu item that will "unhide" the toolbar is , in my opinion, very poor programming. When typing away it is not that hard to accidentally hit the ALT key. Then if you didn't know it had this effect, you'd wonder what happened, and not be able to find a way to rectify it, (other than having to use google chrome to google firefox help.