Calling index.php not single.php on homepage

Hi,

The site I’m currently building was set up so that the first page (base directory) showed a flash intro (written into index.php), which automatically redirected to the home page, a page calling ‘home.php’ template.

This was working fine, but now, for some reason typing in the homepage address takes you to the latest posts page (‘single.php’). I know that’s how it’s set up in the Reading panel, but previously ‘index.php’ was called first.

Is there any way of making sure index.php is called on the home page, and not single.php? Or was the fact this worked initially a freak occurrence?