Usually at the back of the modem has an inside button (it has the tag "reset") that u can push it with the help of a object that has a point. (e.g pencil).
wiggle the speaker plug where it goes into the jack on the computer
substitute another pair of speakers
the speaker icon should be on the bottom right of the screen, you may need to right click there and push "Show All Icons"
Or in Control Panel under Sound