This is the nutiest thing.  I plugged my new USB headset into my laptop and it worked fine.  I unplugged the speakers from the new computer and plugged them into my laptop, and they worked fine.  I then plugged the headphones into the new computer, and I had sound.  Next, I unplugged the headphones and then plugged the speakers into the front jack, and they worked (screen popped up to confirm I was using the front jack).  Moved them to the rear of the computer, confirmed I was now using the rear jack, and they didn't work.  Moved them back to the front, and they work.