Recently the subwoofer connected to my computer has stopped working, despite the fact that its worked fine in the past. The two other speakers i have currently hooked up to the computer work fine. Weirdly, whenever i plug in the subwoofer in the back of my pc, the configuration settings (where you choose if the device you plugged is a speaker, headphones, mic, subwoofer, etc) appear as normal, despite the sub not working. The model of subwoofer is an INSPIRE T7700, made by Creative Labs.
Try connecting the subwoofer to an audio output you know works (the green front audio out).
Try a different cable
When a sub amp breaks it may not give you any warning. If you pin it down to the sub you can try opening it and see if there is some kind of fuse or blown component.