404 error or Error: PHP is not running

I have been trying for a week to get this to work. I have tried downloading new WordPress several times and starting new several times. I am using LiquidSquid Hosting and they do support PHP. It is even one of the recommended hosting sites of WordPress. There was another forum that had a similar problem. I tried their solution of loading all files in my web/content and then load it: http://www.prodentalsource.com/web/content/wp-admin/install.com (with or without .com, or .php). and I get a 404 error. Any ideas on what I can try? Thanks