You get an alert about resending POST data if you go back to a page or refresh a page that was previously requested from the server by submitting form data via a (hidden) POST form.<br /> Firefox can only make sure to get the same page by resending that POST form.<br /> Firefox doesn't know what that form data means, so Firefox asks for confirmation before resending that form data as such an action can cause you to repeat an action and buy another item or post a message another time.<br /> A way to prevent that pop-up is not to use the Back button, but to open links from a page that was requested from a server by sending a POST form in a new tab (window) with a middle-click or a Ctrl + left-click.<br /> Then you can close that tab or window to go back.<br /> ---- Other things that need your attention: Your above posted system details show outdated plugin(s) with known security and stability risks that you should update. # Shockwave Flash 10.0 r45 # Next Generation Java Plug-in 1.6.0_17 for Mozilla browsers Update the [[Managing the Flash plugin|Flash]] plugin to the latest version. *http://www.adobe.com/software/flash/about/ Update the [[Java]] plugin to the latest version. *http://www.oracle.com/technetwork/java/javase/downloads/index.html (Java Platform: Download JRE)