My laptop's LCD is solid, uniform gray and displays no lines, pixels, characters or other markings. I take it this means the backlight is on, right? What can I do?

The computer works completely fine when an external monitor is attached.

This happened after I took the laptop apart to clean dust out of the fan.

The LCD is connected to the motherboard by one of those connector plug things with maybe 40 tiny wires going into it. Unplugging this required a modest amount of pressure, but I treat these things very delicately. Could I nevertheless have damaged it?

Apart from that there has been no damage to the monitor or laptop of any kind, everything runs fine, and I never had any problems with the monitor.

I used an anti-static wrist strap and anyway I would think I'm in a pretty low static environment: a room in my house with bare wood floors, no curtains, no other electronic equipment.

System details in my sig.

Many thanks!