We have a user who docks a dell inspiron laptop on to an e-port docking station. The docking station has two external displays. Whenever he docks his laptop, the VGA display always cuts off. The monitor is black but the power light is on. His desktop is still extended as if the VGA monitor was on.
There is one DVI port and one VGA port. The VGA always has the issue, the DVI always works flawlessly. I've tried different monitors and it's always the same thing. I've also tried a different e-port docking station and the same issue.
The only way he can fix this is to unplug the power cable from the monitor in the VGA port and plug it back in.
The only time I've ever seen this was when a user had a video card with two VGA ports and one VGA port on the motherboard. If the user plugged one monitor into the motherboard and one into the video card, the same issue would arise. It was resolved by having the user plug both monitors into the video card.