First of all, it is important to diagnose the cause of the unexpected network card disconnect. There are a number of potential causes such as hardware issues, software conflicts, and environmental factors, so it is important to identify the culprit before troubleshooting.
A simple diagnostic test involves plugging the network cable directly into another device, and seeing if it stays connected. If it does, then the issue may be within the computer itself.
If the connection drops when connected directly to the other device, then the issue may be environmental, such as interference. This can be identified by moving the network cable around or trying to connect it in a different location.
It is also possible that the issue is caused by a software conflict. Some programs can interfere with the computer’s ability to connect to a network. To check for this, try uninstalling any recently installed programs that may have caused an issue.
If nothing seems to work, then the issue may be hardware-related. Try replacing the network card with a new one. It is also possible to troubleshoot the existing card by checking for outdated firmware, or updating the drivers.
As a last resort, it is possible to reset the computer’s system settings. To do this, go to Control Panel and select “System and Security”. Select “Recovery” and then select “Advanced Options”. Choose “System Restore” and select a restore point before the problem began.
Following these steps should help to fix an unexpected network card disconnect in Windows. However, it is always best to consult a qualified technician before attempting any of these steps.