To setup computers with Internet Explorer to automatically dial, perform the following steps:

Click the Start Menu and select Settings, then Control Panels.

Double Click on the icon called Internet Options.

Click on the tab at the top that says Connections

Make sure the dot is placed next to Always Dial My Default Connection.
If does not say Default next to it in the box at the top, click once on it then click on the Set Default button. Click the Settings button.

Click OK 2 times, and you are ready to go.