how can i get internet in my compaq presario 1200


Translate into English: See the card on the back of your desktop? It should look like a phone cable or network cable. Get a white cable that is connected to your router, plugged in to either 1,2,3,4,5 etc. Then connect that white cable to the card.
 


The Compaq Presario 1200 is a laptop (of sorts!), so calling it a "desktop" in your reply isn't helping you to "translate into English"