Why can't I duplicate laptop's screen to HdTv?

How do i connect my laptop to my tv.?

• I have two laptops. One has a broken screen. I hooked the new one, that is not broken, to the hdtv using rgb and it worked fine. When i hooked the broken screen laptop to the tv it would not work. With the broken screen laptop, you cant see the screen at all so i cant change any of the setting. I also tried pressing the display setting button on it as well, but still nothing. I hooked it up to a monitor but that did no work either. how can i connect it.

• Answer:

  Laptop to TV cable connections are not rocket science. They’re easy and simple. All you need is the proper cable and a few adjustments to your laptop settings. If your computer has a video-out on it, then you can use a regular RCA cord to plug it into a device with a video-in. Of course you'll need to go into the desktop settings and play around with the available monitors. Using your TV as your monitor only or extending it to it.