It seems that IE also uses port 80. I have no idea why IE stopped working. I can't remember doing anything. It works in safe mode. I'm currently trying to solve the problem.
I was using a trial version of Symantec Internet Security, but since that expired, I'm using the windows firewall. I'm working on Vista Home Edition. I've scanned the computer with AVG antispyware, and only found the usual tracking cookies, which I always delete. I'm currently scanning with avast (if it finds anything unupdated!)
I'm not sure what can still be blocking IE (I've deactivated and deinstalled a large majority of the programs, including all the protection programs), but whatever it is, it seems to be blocking port 80 (I have no idea what Mozilla uses). Dreamweaver also won't connect.
El