Already Installed?

I have just gotten to the fourth step in the installation process, where I have placed my files on my site. Once I opened wp-admin/install.php, it says I have already installed WordPress, which isn’t true, this is my first attempt.

Then when I attempt to access my wp-admin subfolder it says “Your database is out-of-date. Please upgrade.” I click the link to upgrade and I wind up at a page that says if I see this message I am already upgraded, so I click the link it tells me to, and I am taken back to my wp-admin subfolder that says “Your database is out-of-date. Please upgrade.”

And so, I am in an endless loop.

Please Help!

Thank you.