If your PC’s behavior or error messages indicate that network communication is down, first ensure that the network is stable, that other machines are working normally, and that problems with the PC’s network card are ruled out.
Some of the newer PCs have a function that not only shuts down the screen after a certain length of time (screen saver) but also reduces the speed of disks and processors. Refer to the manual for your PC’s operating system and disable this function.