The permissions there seem to be OK, so hopefully it's an inheritance thing that can be adjusted.
Open Windows Explorer.
Navigate to teh C: drive, and right-click on the Windows folder - select Properties
Click on teh Security tab.
Click on Advanced.
Click on the Owner tab.
(The owner should be TrustedInstaller)
Click on Edit and highlight Administrators
Click Apply (note the warning), and OK out to Explorer.
Get back to the Advanced section again.
now put a tick in the 'Replace all child object permissions....' box, and click OK - it'll take a while, and you'll geta few error messages along the way (click Continue)
Now check the Windows folders icons again - has that removed the locks?
post back with the same ICACLS results as earlier so we can see if anything has changed.
If there has been change, please post a new MGADiag report as well.