As I watch video -- either with VLC or on youtube or hulu - the audio starts off fine, but within seconds becomes corrupted. I can hear background noises of the video and music fine, but I cannot hear dialogue. Sometimes some of the dialogue comes back, but it is very faint. Some of these videos were downloaded from the internet, so I cleared my cache on Firefox. I also went to Disk Utility and clicked on "repair disk permissions." Doing those two things have not repaired my issue. What else can I do to fix this? Thank you for any help you can provide. ADDING: I have shut down and restarted my computer a few times. Every time I do, the audio seems to be fine... for about 30 seconds, and then begins to get corrupted again.