You could try reinstalling your sound device driver. If you have a integrated soundcard on your motherboard, you might need to reinstall your OS. //EDIT here: forgot to add, that this isn't the first time this has been a issue and reinstalling OS was the final cure for this, but keep it as final fix! And who knows if VIRUS has lurked in your system Do a scan also. If you have external soundcard, disable the motherboard sound device, these 2 together often cause issues. Also try running et on 1 core only: run et -> press ctrl + alt + delete -> find et on running processes list and click mouse right button -> select "set affinity" -> uncheck cpu1 box (or vice versa).