Had this problem previously with an existing 7.3 site. Applied the latest patch, deleted and rebuilt the nuke_authors table from scratch, deleted cookies, and life is good.
Still unable to login. I deleted all my browser coockies, removed the contents of the nuke_authors table, re-created the GOD and account and I still couldn't login.
I'm running 7.3 and before I could apply the security patches I got hacked. I deleted the contents of the nuke_authors table and opened admin.php. I created a new GOD account and set the password, but ...