I assume that you do have a webserver running? (IIS ?)
if you right click on the website in the IIS control pannel and select properties you'll see a page with some tabs at the top,
click the documents tab.
in the box in the ceter you'll see default.htm and default.asp (or something simillar) sre the default pages
use the add button to add index.html to this list of default served pages.