Blog Is Invisible

Try:
– switching to the default theme by renaming your current theme’s folder using FTP or whatever file management application your host provides.

– resetting the plugins folder by FTP or phpMyAdmin.

Tried both suggestions with no results. I also found and deleted the .maintenance file, even though I wasn’t seeing the “Briefly unavailable for scheduled maintenance…” message. What do you suggest now?

Have you tried re-running the upgrade manually using /wp-admin/upgrade.php?

Yes, I got this message: No Upgrade Required

Your WordPress database is already up-to-date!

Do you have a recent database backup?

Yes.

Try setting up a new database and importing the backup into it. Then edit your wp-config.php file to point to the new database.