Origineel bericht door: Ken ,
Could you try one thing before going after the hardware. Restart the computer and hold down the Shift key until the blue screen comes up and then for about 30 seconds more. I have seen on other machines that when there have been a disturbance with the system, going into safe mode sometimes lets the system recover and then the restart after that it comes up. It won't hurt to try and see if by chance it helps.