If you cannot see other computers on your network in Windows, then you need to enable network discovery and file sharing feature to see all the computers.

I took the 5GHz connected computer, disconnected from the network, and reconnected to the 2.4GHz network. No dice, the two wireless computers still cannot see each other.

My problem is: when Computer A is connected wirelessly, it cannot see Computer B on the network, nor can I establish an RDP connection via IP address.