Installer not showing up
I realize your situation isn't identical the one discussed here but I would try running the upgrade script to see if it resolves your issue.

If not - one important change is to make sure you remove the CiviCRM database tables when reinstalling!  If you installed to a separate database from WordPress, that should be easy.  If not, and it's not practical to restore from a backup, you can drop all tables with a prefix of CiviCRM.