|Are they external speakers plugged into the audio jack on the back of a desktop tower, with or without an external power source? Are they inbuilt speakers in a laptop?|
Did they ever work? What troubleshooting steps have you already taken so we don't have to go over old ground?
eg: Are they plugged in? Are they turned on? Have you checked volume control?
Have you looked in Device Manager at sound/audio devices and checked whether or not the sound drivers are installed and the device is reported as functioning?
Goin' Fishin' (Some day)