Hello. As of today I've been having some extremely annoying issues. About six minutes into a YouTube video, I noticed that the video started lagging / freezing. It could pause for two seconds, then lose audio, then work as normal, then pause etc. etc. I restarted my computer like usual, but kept having the problem. Switching from Chrome to Safari (with newest Flash) did not help. I have the newest software update to Snow Leopard. I later tried listening to music. It would start doing the same thing, pausing the music, and jumping in and out of headphones. I decided to see what would happen if I plug out the headphones, but that gives me even more issues. I become unable to change the volume. The little icon with the speaker turns grey, and when I press the "change volume" buttons nothing happens. I've been looking at the activity monitor, trying to find strange processes, but I don't see anything out of the usual. The last app I installed was MKVmerge or something, but that was two days ago. I have an iMac from 2010. 4GB's RAM, i3 processor. Still running Snow Leopard (like I said previously, I think). I've done everything I thought would help, but it didn't get me anywhere. Please, help if you can.