You can easily disable port 445 on your computer. To do so follow these instructions:
1. Open regedit and go to: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\NetBT\Parameters
2. Under that key locate the entry named TransportBindName.
3. Double click the TransportBindName entry and then delete it's default value, thus giving it a blank value.
4. Reboot for change to take effect.
5. After rebooting open a command prompt and run netstat -an to verify that your computer is no longer listening on port 445.