Okay, so lately my sound has been glitching out slightly. Whenever a sound is made, it repeats it, like it's studdering. If you need more information, just ask. I am only using, optifine and zombe's pack, which, after a few tests, don't seem to affect it. It never used to do this before, just recently.
Virusscanner? What do you mean by that? The snooper?