I do use a firewall - Kerio Personal Firewall 4.04. Hasn’t given me any problems. I don’t have any other online backup stuff, or other low-level stuff, as far as I know. We do tend to have a lot of applications loaded though - things like YahooPOPs, Hotmail Popper, AC42 (stay connected to the net), often MSN Messenger or Trillian, etc. I have loaded Kazaa Lite, and use it occasionally, but not recently.

Task manager does indeed show memory use growing - but significant amounts only when Avast is loaded. It’s hard to pin down though, because we very rarely reboot, and we use a lot of applications.