I DELETED from the DMSGUESTBOOK folder from the wp-content/plugins folder.
The result was: “The plugin dmsguestbook/admin.php has been deactivated due to an error: Plugin file does not exist.”
HOWEVER, the problem has now been SOLVED – I can manage pugins, I can edit posts and I can edit pages!
I am ALSO not able to Edit Page (i.e., it is also blank).
