Issue Installing over Existing Website

Hi, I’m really new to website building so bear with me. We had an existing crude website that we’re trying to replace with something powered by WordPress. I followed the instructions for the manual install on GoDaddy’s hosting control center. I created a MySQL database and I uploaded the WordPress files into the HTML Directory and I edited the config.php file to reflect the proper username, password, etc. When I try to access the install page however, I’m getting the 404 page error response. Is this because I still have prior existing files in the HTML directory or is there something else I’m doing wrong. Thanks for your time.