CPU running slow (0.48GHz instead of 2.10GHz) !?

Recently ran into a laptop performance issue after doing the monthly updates for Windows 10 and suddenly my Intel CPU is running super slow.   Reset power plans to default.   Reset BIOS to default.   Even disabled power idle, C-step, throttling in BIOS.  Nope.   Reset OS saving files, and then thought it was working until I logged into cloud account and back to slow again.  Now it's the profile.  Full nuke from DVD install.   Now running slow with default local only account.      Pulled battery, running with AC adapter only. Nope.   Run battery only. Nope.    Local Throttleshop utility to see if I could force CPU into gear.  Nope, utility showed all cores and multiples as normal, no speedstep active, CPU temperature safe and in the green.  Boot from Linux ISO image to rule out Microsoft, and it is slow there too.

Reboot PC again and decide to test using the built-in diag utility which I forgot was even there.   CPU processor fan fails the test.     Well, now all is clear.   Apparently CPU boots normal, then after a few minutes the sanity check between CPU, motherboard and fan controller shows fail and locks CPU at 20% maximum speed.  I'll never overheat and burn-up the CPU so I guess that is good but nowhere in event logs or boot-up sequence was there an alert this problem existed.

A can of compressed air has the processor fan back to working, at least until an OEM replacement can arrive.  Maybe this post will save someone else a waste of time re-imaging, and troubleshooting.