Blank screen on laptop

[FredPuli43]

hp compaq Presario CQ56. Power is on, screen is completely black, double clicking 'left mouse' doesn't bring up the screen,keyboard not responding.
What's the cure, please? The wi-fi light is showing off, but the key doesn't respond,of course , but the wi-fi is working on the other computer.

[Pro_sparky]

Hi Fred, small cover on the bottom of the laptop, open it up with a small posi screwdriver, remove 1 stick of ram if there is 2 sticks.If still no joy,swap the ram with the other one so you try each ram in turn.
If there is only one stick you will have to find another ram stick you know that works. There are numerous problems that can cause this but ram is an easy start.

[FredPuli43]

Ta!