First things first, let's make sure the computers can ping each other across the network. To do this, we need to know the IP addresses of both computers. If you already know them, you can skip this step. If not, try the following on one of the two computers, doesn't matter which: Start by going to the command prompt (Start->Run, type cmd, hit enter). At the prompt, type ipconfig and hit enter. What you are looking for is the IP address here. Write it down. Then go to the other computer and do the same thing. Now that we have both of the IP addresses, we will check to see if the computers can communicate on a low level. Still at the command prompt, type: ping [iP address of other PC] and hit enter. It will end up being something like: ping 192.168.1.100. If you get replies, good. We can move on to the next step. If it says that the request timed out, we need to diagnose a little more.