Unable to refresh Windows Experience Index

Windows Experience Index will not refresh. Everytime I try, I get the error
message
"Windows was unable to calculate the Windows Experience Index because the
user cancelled the assessment"
I have deleted the xml file using the advice in previous posts
(search %SYSTEMROOT%\Performance\WinSat\DataStore)

There are suggestions to edit the registry by navigating to
HKEY_CURRENT_USER \ SOFTWARE \ Policies \ Microsoft \ Windows \ Control
Panel \ Performance Control Panel

In the right-hand pane, delete the value named PerfcplEnabled (if found).

-And/Or-

HKEY_LOCAL_MACHINE \ SOFTWARE \ Policies \ Microsoft \ Windows \ Control
Panel \ Performance Control Panel

In the right-hand pane, delete the value named PerfcplEnabled (if found).

However, I do not have the entry Control Panel in the Windows heading.

What now??

--
as you wander through this life, whatever be your goal, remember to keep
your eye upon the doughnut, and not upon the hole