HP Pavilion dv2000. My laptop's sound has not worked for about a week now. I'm unsure why this

Question

My laptop's sound has not worked for about a week now. I'm unsure why this suddenly occured, although the last time the sound worked the battery died as I was playing a DVD that did include sound.

I have checked the volume, mute features, and everything else under the Sound control panel. My battery now lasts probably 45 minutes without being charged, but I'm hoping I don't already need a new battery because of the sound.

Any suggestions on how to get my sound back? (The volume ticker still makes a noise but nothing else does)