None of the other devices (laptops, several smart phones, even visitors with laptops) experience this problem.
I cannot test the PC workstation with a cable - too far away from router.
PROBLEM:
After start-up my Windows 10 desktop PC connects automatically to WiFi with Internet access. GoogleDrive and Dropbox sync successfully. About 2 to 4 minutes after start-up, the Internet access is disconnected although the WiFi connection remains intact. Internet is still available on...