100% CPU usage after Windows update. How to Fix this issue by the below steps.

Run the following two commands, which set the IDLEDISABLE setting back to "0" and then re-applies the power management configuration.

Open (Admin) CMD window

First switch to:

C:\WINDOWS\system32>

Copy this string and hit enter:

PowerCfg /SETACVALUEINDEX SCHEME_CURRENT SUB_PROCESSOR IDLEDISABLE 000

Then copy this string and hit enter:

PowerCfg /SETACTIVE SCHEME_CURRENT

DONE! The 100% CPU issue is gone showing a real percentage load.