Ok, I was playing a game and the sound cut. The speakers were still on, so I closed the game and checked the sound settings, and lo and behold, the mute had been turned on. All fine untill the next day when the same thing happend. This time when I went to turn the mute off, the tick would stay in the box and only the sound that was supposed to be from the left speaker would work. I have checked for viruses, spyware and adware and this hasn't fixed the problem.