Why aren't I getting any sound from my laptop?

First thing, I'd go to control panel, bring up "Hardware & Sound," then click "Sound," and check the speakers on default. Make sure you see action on the measuring bars to the right. I've had laptops that would phantomly reset their input and output settings on their own.

If this is a new problem, out of the blue....I'd not be surprised if it's a setting or maybe even some mistake in communication between the speakers and the closed lid switch. The good news is you've got some troubleshooting to be done before giving in and accepting total speaker failure.