I have a Windows 7 laptop, which I run connected to an external screen. For some reason, within the past three weeks, whenever the screen becomes especially dark for a few seconds it fades completely to black.
Here's an example of happens:
- I minimize all windows. The screen shows my desktop, which is currently blank (black). All of the desktop icons are visible, as is the start button and the toolbar at the bottom of the screen.
- Immediately (within 1 second) the screen starts fading to black, turning pitch black within 3 seconds.
- Moving the mouse does nothing to restore the screen.
- If I do something like hit the Windows key on my keyboard or alt-tab to bring up another window, it immediately fades back in.
Some other oddness: this has to do with the brightness of the screen. Setting a bright background stops it from happening, while navigating my web browser to an all-black page causes it to happen. If I get just the right level of darkness, it will fade out about halfway and then flicker until I change the screen.
Another interesting thing: if I have both the laptop and the desktop screen mirrored, and navigate to an all-black page, only the desktop screen fades.
What's going on?