Also, when in the command prompt, run:
and look for your local area connection adapter's IP address. Do this on all three machines and make sure you're in the same subnet (Likely 192.168.x.y). Make sure the 'x' matches on all three computers, else you may have a static IP address assigned, preventing you to access the proper subnet.
Note in the image that two of the adapters are reporting a 169.*.*.* address. This is a default IP the computer will assign itself if it is having trouble contacting a DHCP server.