Laptop to LCD

The computer screen will not project to the tripod screen, I don’t understand whats wrong. I am doing this for the first time, and I think I have the right stuff connected. Any ideas where I can go to make sure? I am using a serial connrection, hmmm, maybe I shoud see if there is a usb (that I am not using) to connect, I am clearly confused here….
Thanks
Wayne Reno, Nv.