On my PC, I have an audio jack in the back and the front. My 2.1 speaker is hooked to the back. I was trying out a cheap pair of headphones and decided to plug them in while the speaker system was turned on. As soon as I plugged them in, I heard a pop sound from the speakers. After that I could not play any sound on either jack. I shut down several times and the sound came back to my speaker system. Any idea what happened? I am really frightened to use the front jack now.