I am seeing similar behavior to the OP.
I am trying to connect a Foscam FI9831W to Blue Iris (3.x) and get the "No Signal" display.
PC is a Dell I5 running win8.1.
Camera is a fixed IP (192.168.4.100 [PC is 192.168.4.10] both are directly wired to a netgear switch) and works fine with...