Have you tried looking at the headers - the server responses when you request the URL that you expect to see the site at? That can usually help you narrow down the causes of an error like this. If you don't use FireFox browser with LiveHeaders, there is a tool in the WebmasterWorld Free Tools Library (see the link in the menu at the top of the page).
I installed one once maybe 7 years ago, I didn't like the way it worked for what I was trying to do and uninstalled it. My suggestion is not Joomla specific, it is for every site. LiveHeaders lets you see what the browser is requesting and what response it is receiving so you can narrow down the source of issues.
I've been using Joomla since the Mambo days (10+ years), it's always just worked for me. It should take about ten minutes to get it set up on a test server. Sorry to hear it didn't work out for you. If you think about retrying it, give me a shout.