Laptop Monitor at 5% brightness

I booted into Windows and updated Norton Antivirus and then rebooted. After rebooting, it reached Windows and then after about a minute the monitor turned black but the computer was still running. The monitor has not turned off but is only displaying at roughly 5% brightness. When I plugged in another LCD monitor it works. This makes me think it is a problem with the monitor rather than settings or configurations. It was working fine last night.

 

Some of the things which could have caused the problem are:

The computer travelling in the car for 10 hours today.

Updating Norton Antivirus (although the monitor is also black after booting into linux or bios)

A loose cable connection?

 

Do you think the problem is with the monitor itself or computer settings?  Could there be another explanation I have not thought of?