Tey are not really all that dangerous but let me explain them to you jsut to make sure theyre suited for you. 135 is a tcp/udp port imagine tcp as being tiny bits of data that can heal themselves, and udp being a connectionless type of information. 135 basically keeps tabs on whats going on outside the network. Can it be breached? yeah what are the chances? nil to non if it's your home machine. 139 is your netbios imagine that as being your bios that is sent to all the other computers on your network to help keep things in order. In all honesty 135 and 139 are not much of a threat but if your truly paranoid much like myself, then I agree with Isotronics in getting a firewall. I hope I was of some help.