My Dell Optiplex 980 (Win 10 16.299, 8 gb RAM) has been working fine, until this morning, when on waking up from sleep it abruptly slowed to a crawl. That's 'crawl' as in taking 3 minutes to open...

Good try, and thanks, but mine were already disabled.

I have 3 machines in a home workgroup, which were all seeing each other and networking fine. Since a few days ago the Windows 10 Home (Lenovo All-in-one) has gone blind, can see no computer beyond...