Re: how to find the last known IP of...
If you are his friend on MSN then do the following:
Send him a file (Picture/Song/Anything)and hope that he accepts it. If he does, good this opens a direct connection to his computer.
Click Windows Key + R (This will open up the command promp) and type "netstat -b" look at all the I.P's that "msn.exe" (Or whatever chat client you use) is connected too. It should just show a plain I.P connected to a random port. This is his I.P
Intel i7 4770k 3.50ghz, 32gb Corsair Vengeance RAM (8x4 kit), 2 x 2TB WD Black HHD, nVidia 770GTX 4gb OC, Asus Z87-A Motherboard, running Windows 7 64 bit.