i had a problem, my existing firewall did not work properly after i installed the service pack, even when the mircosoft one was switched off!.. i had to uninstall (my free firewall) so that i could even get an connection....out/in, not sure why , the service pack must have instaled some new files that both firewallls use.. or something..
i have the mircosft one switch on now but when i have the time, will get a proper one. or wait until i get a new router. with hardware firewall. (so buy my names, so iam safe on the web!!)
so I was without web connection for about 2 hours before i realise how to get round the problem.
in the update it probly says somethign about using thirdparty firewalls but of course i never read those things !! (maybe i will in the future, or maybe not)
wilco