You should re-install the driver's for the video-card. It sounds as if you should have options which aren't present. use the cd that came with the card or you can search for the driver using google.
http://support.asus.com/download/dow...Language=en-us
also installing a drive is pretty simple. you simply need to connect the power and a data connection to the motherboard. i'm sure the computer experts in the computer forum could answer this better, but since you have (i'm assuming) a dvd player, you would just turn off your computer, unplug the dvd player, put the dvd burner in its place and connect the burner as the player was previously connected. turn on the computer and install the driver using the cd.