Sony Vaio screen is black?

My sony vaio fw screen goes black when i try to switch a video(youtube)to full screen,but still audio works?

• I can watch videos on youtube for example, on the regular small screen, but if i try to switch to the full screen size, the screen goes completely black, but the audio still continues playing. The screen doesn't return until I press escape, then it goes back to the small screen. Does anyone know what to do?

• Answer:

  The flash is badly installed. Uninstall the present one, go to http://www.adobe.com/products/flashplayer/ , click on Download, click on Download and select SAVE, not Run, when the download ends close the browser and double click on the file you downloaded. When the install is done reboot and go to wherever you want and test it.