I have an ATI X1650 with two lcd, using the analog cable in both of them, I can´t complain about anything everything is working fine, using DisplayFusion to handle windows between both monitors.
Well can you ping any computers adress from it? if so try typing "\\192.168.1.10" <-- example IP from destination computer could be different. just type it in the adress bar instead of "\\BLACKDOG" IP should be blackdog´s adress.