The LCD probably has an outlet like one of these, more likely the bottom one. It could have a VGA out as well.
Notice the two are different and they are not interchangeable. Your graphics card needs to have the same one that the LCD has. If it's a decent card it will have both VGA and DVI-I jacks like this:
If you only have the blue VGA on your computer then you need a VGA-DVI adapter like this