It definitely sounds like a firewall problem - which one are you using? Also, you haven't got the Windows Firewall running as well, have you? Some firewalls don't 'switch off' by simply disabling them, once running. You may have to go into the firewall options, tell it not to start with Windows, then reboot, to actually be free of it, but obviously don't spend too long online without it. Just one other thing, I'm not really sure how they work, but do you have to give permission, via the firewall, for the router to access the internet?