Obviously you want to rebuild the network when the problem is in a single computer.
This thread is intriguing. By your advanced powers of observation you know accurately what I think. On the other hand, by my own lack of observational powers I still struggle to understand your setup. Here are some of the things one considers when dealing with a Remote Desktop configuration:
- Are the host and the problem machine on the same network, i.e. do they share the same subnet?
- Are they on a VPN?
- Are they on different networks, connecting through one or several routers?
- What port do you use for the RDP connection?
- Do the routers have a tunnel for this port?
- Do you access the host by IP address or by NetBIOS name?
- Do you use an .rdp profile file?
- Does the problem persist while all firewalls are turned off?
Each of these items is important when setting up a RDP connection.