Not sure if this helps, but in a motherboard problem I mentioned here a little while back, the motherboard sound hardware had jumpers which identified to the motherboard whether sound was to the rear panel or the front panel. If you wanted sound to the front panel, you had to remove the jumpers and get a cable to connect the sound device to the front panel. If you wanted audio to the rear panel, you left the jumpers in place. (My problem was that neither the jumpers nor the cable were present, meaning that I had no sound at all.) I've certainly known PCs in the past where you could have sound to the rear or front, but not both. It may be a function of some motherboard designs. As such, it might be worth downloading the manual for your motherboard to see if the same is true for yours.

This one has got me quite intrigued.

In theory, attaching the front panel audio cable to the motherboard pins could act instead of the jumpers on the pins - so there should be no reason why you couldn't have front and rear audio. I'm not sure though...

However: even if that does turn out to be the problem - that you need a cable - sourcing one looks as if it could be a real can of worms. The normally-reliable eBay has a number of cables, but they're all manufacturer-specific. And Googling for a cable for your motherboard indicates lots of interest - but nowhere to buy one...

Most cases these days come with the necessary cable to fit on a socket on the motherboard. What is your motherboard? this will tell you if you are unsure, Belarc.

Are you saying that The headphones do not work where ever they are plugged in,front or back?