Perhaps if you tell us why you want to do this, we can provide a good, and safe solution for you.
I personally do not want to be able to do this because it requires Network Discovery to be enabled. That may expose those systems to potential security issues. So I have Network Discovery disabled.
For me, when I want to see what devices are connected to my network, the best solution is to look in my router's admin menu at the list of "Attached Devices". This not only shows me which computers are attached, it also shows my network attached printer, network storage device, smart TV, Roku, tablets, wifi connected cell phone, AND any potential unwanted/unauthorized device (perhaps a bad guy or nosy neighbor whizkid) that may be connected to my network.
Note "Attached Devices" is what my Netgear router calls them. Another router may called them Connected Devices or something similar.
If you really want these in Explorer, as far as I know there is no way to actually refresh the display without restarting Explorer. You can do that by restarting the computer, or you can go into Task Manager and under Processes > Name, scroll down to Windows Explorer, right click on Windows Explorer, then select Restart. Just make sure any open files - such as an email you are creating or a Word document - is saved first or you may lose all your most recent changes.
If these off-line devices still appear after rebooting or restarting Windows Explorer, you may have to do a "cold" reboot. By “cold”, I mean shut down the computer and flip the master power switch on the back of the power supply (if your supply has one) to off (or “O”), or unplug the power supply from the wall for about 15 seconds. Then turn the master power switch to on (or “|”), or reconnect the power cable and boot up and see what happens. By totally removing power, you reset the PSU. It also removes the +5Vsb standby voltage all ATX Form Factor power supplies are required to supply whenever the power supply is plugged into the wall and (if applicable) the master power switch is set to on. This standby voltage is distributed throughout several points on the motherboard, including RAM for faster boots and the USB ports too. This also keeps alive several features, including “wake on keyboard” and “wake on mouse”, and the network interface for “Wake on LAN” commands. A cold reboot ensures any device settings that may be held by the standby voltage are released, then reset when power is restored.
