make sure that the file u upload is called index if your just going to your domain name... ie www.domain.com... if there is no index.html/asp/xml/etc etc you will get the 404. also most hosting servers are case sensitive. so, if your going to your page and you type it in as blah.html, when on the server the file is called Blah.HTML, you will get the 404.

htmlgoodies.com is your friend if your a novice at codeing....