Believe me I’ve been doing this for a while and anytime you do an update it will slow down your computer a little bit and if you do several updates at once like with a service pack you will really notice the slow down, don’t take my word for it try doing a N&P, format and install Windows XP on a machine with only 256 MB of RAM and notice how fast everything pops up then start installing each service pack and see if it doesn’t slows down.

In that topic I think hes talking only about sounds related to Avast where as I am talking about problems with system sounds.
I did a search before starting this topic and found a few post similar to my problem but they were old post and running windows 98