This is what I do to make sure they connect. There may be an easier way but this one always works on any systems I use.
My computer > My network places (in the left panel) > View network connections.
Right click local area connection which ever is the one you are using to connect the computer with.
Scroll down the list to Internet protocol (TCP/IP)
Go to "use the following IP address"
Type in the box 126.96.36.199 (on the other computer this should be 188.8.131.52)
press tab so that in the following box it will say 255.255.255.0 and click ok.
You should now connect. You need to either disable your firewall or set it so it allows the connection to the IP addresses I spoke of before.