Use this Win 7 tutorial.
Yes. It is still applicable to Win 10.
I used it at least 3 times when NetWork and Volume were missing from the system tray.
Last time I used it was yesterday. Volume icon was missing.
Go to Option Two
5. To Enable the Network Icon
A) Click/tap on the Download button below to download the file below.
Then continue to step #11 to #15.
Make sure you restart the computer to complete the process.