My JBL Quantum 400 headset isn't working.

Hey, I have a question. I've recently encountered a problem with my JBL Quantum 400 headset. My PC isn't recognizing it. Basically, I can't hear anything through it. The thing is, the headset lights are still on, which should mean it's working, but it isn't. My question is, what can I do now? I've tried a lot of things, like restarting my PC five times for a reason. What can I do now?