no sound in headphones

Apparently, I'm the ONLY person with this problem. Is there a simple fix or something that I missed? I plug my headphones in and there is NO sound. I've checked the volume, I've check the jack to make sure it's in all the way. I just don't understand. I've used my headphone port before, used to work just fine, don't understand why it's not working suddenly now.

HELP!