Upload WordPress to my domain (link MySQL Database, domain and FTP)

I have spent the last 6 hours trying to get WordPress version 3.5.1 to install using 1&1. Closely following an online guide, I have set-up a MySQL database, registered the domain and tried uploading all the files (including the changed wp-config.php). Unfortunately when I go to http://mydomain/wp-admin/install.php I get an error 404. I have gone through and triple checked everything and simply can't get it to work.

It's really frustrating! I'm hoping there's someone out there who can talk me through the install or do it on my behalf. I'm hoping to build my own e-commerce website with the WP platform.

Help!