Made sure those files are in place. Verified that all HTML files are in the proper directory. Checked that any necessary subdirectories have been created and are being addressed properly in your HTML code. If your web pages do not display even after the above have been checked, Check to assure your HTML tags do not contain capital letters, nor do the file names they refer to. Or, if they DO contain capital letters, that the same capitals appear in the file name as well.
Internet servers are case sensitive.
This means that if you type a name in all lowercase letters you are safe. If you type some capital and some lowercase letters, then the files and the HTML tags will need to be identical. Try Doctor HTML or The Web Site Garage once you've uploaded your pages. Use an Internet Search Engine to seek out HTML tutorials and references. One of the best is the Web Developers Virtual Library , or start out with some of the links below.