private void UnsubscribeUserFromAll(string userEmail)
        {
            if (string.IsNullOrEmpty(userEmail))
            {
                return;
            }
            if (!Email.IsValidEmailAddressSyntax(userEmail))
            {
                return;
            }


            SiteUser user = SiteUser.GetByEmail(siteSettings, userEmail);

            if (user == null)
            {
                return;
            }
            if (user.UserGuid == Guid.Empty)
            {
                return;
            }

            ForumThread.UnsubscribeAll(user.UserId);
            Forum.UnsubscribeAll(user.UserId);

            lblUnsubscribe.Text = Resources.ForumResources.AdminUnsubscribeUserComplete;
        }