2.0.1 will not display index.php

For some reason, when I try to get into the Site Admin section of my blog, it brings up a directory listing for the directory rather than defaulting and opening the index.php file. Clicking on index.php in the listing opens the page fine. Once I’m done and click on View Site I get the exact same thing.
Wouldn’t be that big of a deal if it was just myself, but this is an internal blog for about 5 people, and I’d rather not have to explain that they need to do this each time they want to get to the blog.
For what it’s worth, it’s WP 2.0.1 with Apache 2.0.55, MySQL 4.1.18 and PHP 4.4.2, all running on a Windows platform.
If anyone has any suggestions, I would definitely appreciate it.

Thanks,
Rod