Better will be uninstall avast and install again after SP2.
Sorry. I wrote not that clear.
I mean, when upgrading Windows XP from SP1 to SP2 it's better uninstall avast! before updating to SP2 and install avast after.
If this was not done before, then, maybe, the user can uninstall avast and install again.
A lot of changes will be made when installing SP2 and the low level programs could suffer because of this, such are antivirus, firewalls, etc.
It's not safe to use just avast! (antivirus) and SpyBot (an on-demand antispyware) and not use a firewall.
If you can't use avast! with Windows Firewall it's better check if it is allowed to connect through Windows firewall.
It's better take some time to understand basics of Windows working before...
