Registry permissions problem in fixing "Access is Denied"

I'm in the process of updating WinXP Pro SP1 to SP2. I am using a full
downloaded update file on a local disk (approx 280M). Got the infamous
"Access is Denied". Found offending registry keys (twice). Keys were .ivf
and vnd.ms.radio. Found them with Read permissions. Managed to get them to
Full and Read permissions. Can't figure out how to get them to Inherited
instead of Not Inherited. Top level key (HKCR) is currently at "Everyone",
instead of the complete list of owners I see on other keys.
I have gone through the export/delete/import process and that didn't seem to
fix the Inherited/Not Inherited status.
Am I being paranoid that I can't get them to Inherited? Any ideas on how to
get them to Inherited status?
Do I need to worry about the top level key HKCR having only one entry
Everyone?