Can anyone suggest what to do ... I pasted a YouTube address into a Word doc ... It was invisible until I pressed enter ... Then I could not type letters. I pressed The blue Fn key and the F keys trying to make it visible. Then the screen went black and then it shutdown. Now when I switch it on it goes to the start page (before the screen to log in) ... Then the screen goes black and it shuts down again. My computer is VAIO and I use Vista. I do not understand the F keys and the blue Fn key functions.