Go through the sticky below, it has lots of info & potential solutions for connection problems:wink:
Connection problems? Check here first!

Rather than disabling firewalls, just use 1 & make sure it's configured properly. Do you see the firewall icon?
A few people have found that they've had to change their router config after upgrading - read the parts about enabling UPnP & port forwarding, in that sticky. If you're stuck, please post back with your system details...post #2 of the sticky will tell you the info we need.