i connected my laptop to the projector and the laptop screen goes black and no picture on the screen how can i fix this please

[Ettenna_1]

why does my laptop screen go black when i connect it to the projector

 

[Ralston18]

More information is needed: what make and model laptop, what make and model projector? What video port: DVI, VGA, HDMI....?

Have you tried another cable.

What are you trying to project - e.g., just the laptop screen? (Which is what I would expect....)

 

[americanaudiophile]

Make sure to set the output to the projector as a second display and set the resolution of that to the native resolution of the projector. If the screen on your laptop is greater than that of the projector you won't get a picture.
Second thing is if you are using HDMI the "handshake" between the PC and projector can be tricky. Sometimes you have to select the PC as your source before you boot the laptop sometimes the reverse. Try it the way you didn't do it before. My own set up requires that the PC be selected before it boots.
Also try different HDMI cable as it can be an issue especially for longer runs. It also affects the "handshake" where the projector detects the laptop.