problem getting rid of old index file

I was running a blog-like web site at http://www.bikeblog.us/ that I was building entirely in Dreamweaver, no PHP or active pages of any kind, and now I’ve installed WordPress there with the address http://www.bikeblog.us/index.php
The problem is that although I don’t see any other index files in the main directory, sometimes I get the old index page, such as when I don’t type in the www before the domain name.
Any advice?
Thanks,
Thomas