The FN key combo that switches displays from internal to external. You elected not to share make and model (even better when people share a link to the laptop manual!) so I can't be specific.
But it's possible to disable the screen with the Fn keys. Fix? Try enabling it again with that key combo.
If you think the laptop screen has failed, connect an external monitor.
Turning on my laptop instead of the Welcome window starting XP, a gray screen appears. It seems as if XP loads correctly but the desktop is a gray screen.
I can go through the function of restarting or turning off with the start button.
The sound of a slow gear or machinery is not operating at full speed.