I have a Sony VAIO laptop (PCG-FX340) that's about 3 years old running Windows XP Home edition. I leave it on most of the time with a 10 minute sleep on it. It was working fine through last night. When I tried to use it this morning, the display is blank. I have an external monitor hooked up now while I am troubleshooting this. I am pretty sure that the LCD back light bulb has not burned out as when I attempt to switch between the external monitor and the laptop monitor, it flickers once, then goes black again. The laptop has not been dropped or otherwise messed with since it last worked. I have tried to adjust the brightness with no success. When it is booting, I don't see any of the DOS activity either. Any thoughts?