Connection to the Internet with Vista can be a problem if it doesn't connect automatically. Many things can foul up the connection!

One of the first things to check it to be sure the modem and router lights are on.

Some quick connect ideas include

 Click the <start button> (Bottom left corner)

 Click <Connect to> and try to connect to the network you want to

If your unable to connect to the network then click on <start button> right click on the <network> and select <properties>

the menu that comes up should be Network and Sharing Center. From there click on the <Diagnose and Repair> button see if you can get it repaired that way.