OK.
Given that:
{
All wireless devices work.
Sometimes the LAN fails. The (direct cable to each PC or device).)
}
It would seem that one or more devices on the LAN is not playing nice. It either has a hardware fault or a improper network setting.
One method is to remove half of the cables, two of the cables, and see if the problem persists. If that solves the issue, then it must be one of the other twon devices that were not connected. But if the problem persists, try the other two.
This is a simple process of elimination. It can be time-consuming, but it is an important technique if you do not have any error messages to work with.
Last, suspect part of the router is failing. The wireless and the hub are separate chips inside the box. the LAN hub may be failing. Most often it is from heat. Try putting the box in a position where it gets more air. Like stand it on end. Or put a desk fan nearby. (That has worked for me!)
