I own a Dell 560 desktop computer and have a slight issue with the sound. I've owned the computer for about 7 months now. The front headphone jack has recently (within the past few days) developed a problem where it crackles when I insert headphones. This hasn't happened for the past 7 months while I owned the computer. When I plug the headphones in the back jack (I usually have speakers plugged in there), I don't notice any crackling. What's gone wrong with the front headphone jack and is there anything I can do to fix it? Thanks!