Screen is black at login screen if display driver is enabled

Maybe it is stuck in projection only display mode. Most laptops have a button combination to cycle through these options and one is to only use external monitor. According to the user manual it is the Fn+f7 key. Try cycling that with the display driver enabled and the computer turned on.

Lenovo x200 user Manual

Have you tried VGA mode? It sounds like its possible that the driver you are using is trying to default the screen to a resolution that is not supported by the monitor itself. Do you have an additional external display that you can hook it up to, and see if it broadcasts to that properly?

Also, please try VGA mode, and see if you can adjust the resolution from there to the native for the LCD.

EDIT: Irony in its finest form. I currently have a Dell Latitude E6410 with the EXACT same issue. Works great on external display with drivers installed. Works great on internal LCD with NO drivers installed. Install drivers? No longer works on internal. Dell is shipping me a motherboard, not sure why, but they seem to think the video card is bad. I will update once it gets here and I replace it. The E6410 is using the Intel HD graphics chip.