Instructions on how to disable Universal-Plug-and-Play under Windows 7:
Go to Start → Settings
In the settings search for Services and select Services (local)
Search for UPNP-Device host, right-click and select Properties
If Status is Started, please click Stop. Set Startup type to disabled, save with Apply and OK
Next search for SSDP-Search, right-click and select Properties
If the SSDP-Search is running, set it to Stopped. Set Startup type to disabled, save with Apply and OK
Close all windows and reboot your computer
Now you have to unlock the network socket.