can not go full screen in farmville when I click on toggle full screen

when playing farmville on facebook I can not togle full screen, it just freezes up or goes to a blank screen

Please advise about the full screen going blank

You can try if it works if you disable OOPP (Out-Of-Process-Plugins). You can set the prefs dom.ipc.plugins.enabled.* to false on the about:config page to disable the plugin-container process. dom.ipc.plugins.enabled (currently false by default) dom.ipc.plugins.enabled.npswf32.dll (Flash)

To open the about:config page, type about:config in the location (address) bar and press the Enter key, just like you type the url of a website to open a website. If you see a warning then you can confirm that you want to access that page.

You can also try to disable the hardware acceleration in the Flash Player: Flash videos won't play full screen Flash "Display settings" window: http://www.macromedia.com/support/documentation/en/flashplayer/help/help01.html