I have Vista Ultimate, with several user accounts configured.

For one of the accounts, WMP will no longer load the media library.
Folders added to the library through the 'Add to Library' dialog are not
retained (re-opening the dialog shows no folders being monitored).

If I select 'Media Sharing...' from the Library drop down I get the message
"Media sharing has been turned off because a required Windows setting or
component has changed. For additional assistance, click Web Help."

Following the instructions on the Web Help page
(<http://www.microsoft.com/windows/windowsmedia/player/webhelp/default.aspx?&mpver
=11.0.6000.6324&id=C00D0FF4&contextid=233&originalid=C00D0FF4>):

1. WMP Network Sharing service is running OK
2. Ownership of WMP database folder is OK
3. Looking in the registry under
HKLM\Software\Microsoft\MediaPlayer\Preferences\HME, I find a key that I
cannot change the permissions of, delete or add keys to.

The message I get when I select the key is "{key} cannot be opened.  An
error is preventing this key from being opened.  Details: Access is denied."

If I export the HME key and sub-keys, the problem key does not appear in the
.reg file.

I am doing this under an admistrator account.  I can assess other keys (for
different user accounts) under HME without problems.

Do I have a corrupt WMP registry key?  If so, what can I do to resolve this?
I cannot find any method of repairing WMP.

Thanks,
Simon