Did you download anything recently that was from a third party site? Even if you didn't, try downloading and scanning with Spybot and Avast.
Other than that, I don't know what else to suggest; I'm not good with audio problems.
This problem is very complicated so I will try to explain it the best I can. It all started yesterday when I turned on my computer. When I try to play any videos online like on youtube, the sound is static'ky and gurgling to the point where I cannot understand the words at all it's a completely different sound. It's similar to the sound when you have your speakers on too loud but this is not due to that. Also the youtube video uploads but plays very slow like it is in slow motion. Each second takes like 4 seconds. Also on Aol Instant Messanger instead of making the distinct sound when somoene sends you an im it makes a staticky sound. It also did this when I turned on my computer instead of making the sound it makes when your computer turns on it made a werid sound. The weird part is that when I play the songs saved to my WIndows Media PLayer library it plays normally. I have Windows XP.
Please someone help me.