It may be a virus that is causing it or something like Shareza opening a ton of ports and not shutting them. Seems to happen after leaving it on for a while. My ZoneAlarm began using quite a bit of CPU so I had to restart. I did some searching and found this is a common problem but there are no real definite solutions. Do a search using Google for vsmon.exe I will keep testing ZA and Norton but thus far Norton has given me no problems though several claim ZA is easier on your system.