Can i use a ethernet cord for this? What cord do i need?

-I have a laptop and a regular computer i want to hook them together to have two monitors into one. Can i use my ethernet cord or what cord do i need.No, you can't use an ethernet cord for video. Laptops aren't equipped for video-in or for dual output - at best you can show the same images on both.
Ethernet cords are used to get internet.

You'll need a VGA cable.