Borked upgrade from 1.3 to 2.3
In between borked update attempts, are you restoring the database to the pre-update state? By default, Craft will create a database backup and place it in the craft/storage/backups folder during an update that you can use.

If you look at your craft/storage/runtime/logs files you'll be able to 1) see the error that originally happened to cause the failed update and 2) see the error that's preventing the CP from loading.