Yes, you can check a computer for issues or problems by running diagnostic tests and troubleshooting software.
No
NOS (Network Operating System)
Network monitoring software helps a computer run smoothly by monitoring the computer's network and sending alerts to warn that there is a problem long before system failure occurs.
Network and sharing center
No. Use samba to interface to the Windows network.
Networking and telecommunications are responsible for keeping computer network systems running and secure
Network and Sharing Center
If the server is running on the same computer as you are playing on, the IP is "localhost". If it is running on another computer on the same Wi-Fi network, the IP is the computer's internal IP (Google "How to find your internal IP").
Yes, network security should cover all aspects of the network. Whether it is online or off. Having more than one computer connected together increases your chances of having your computers being corrupted.
Check and make sure your not torrenting or doing anything network intensive. You might have a program running that is using up the network or a virus.
The problem could be as simple as a frayed wire (apex)