OK, here's a problem I haven't figured out.

I am connected to the Internet with a wireless connection through Comcast. I can get online and do everything I normally do: but no program except firefox and thunderbird can connect. For instance, my antivirus (avast) can't update; my Ages account can't access the website; Internet explorer can't get on. I've messed with and turned off internet security and Windows firewall and no success. Any suggestions?