Laptop Display black, but I see backlight

YoYo155 said:

Did the PC undergo some sort of shock or fall recently? Nope, no fall. But electricity stopped for a few seconds, but I was on battery.
What changed since the last time you were able to use the display? My laptop was plugged to my external monitor via HDMI. And then when I plugged my laptop via AVI, that's when I noticed I can't switch back to my laptop screen. I never had the setting "Make this main display" before though, but that option is now enabled to be the external monitor, as I can't switch back.
Is it getting very hot? nope
Is it in a humid environment?

nope

It's weird how the screen name will change under Device Manager. It had always been called Vaio, now Display Flat Panel (1024x768). My real display is 1600x900...

Ok, I will try that.

Some other info I thought of, my color and everything seems to be different than before. I don't know whether it's the AVI cable but colors arn't as vibrant now on my external monitor.

When the problem started, I think my color are less vibrant now on my external monitor.

So sorry, I always meant VGA cable.

Low Resolution mode dos not work...Every time I press ENTER on "Low Resolution", it still shows up as 1080P...

So when I go to my Intel Graphics Properties, I only see my external monitor listed, I don't even see my laptop screen..

Post back a screenshot of the Laptop monitor in Device manager, all tabs.

Use the Snipping tool in Start Menu. Attach with paper clip in reply box.