Formatting (style sheets?) glitches when changing address in settings

I have installed word press twice. Both times, I get everything installed, start setting up pages and posts, etc. Then when I go to General Settings to try to change:

WordPress address (URL)
Blog address (URL)

both times it has lost all formatting, and all pages look like standard rich text with no style sheets or formatting, and I can no longer access any options, admin, settings, etc. pages at all. Hitting the back button and changing it back to my root domain URL does not fix the problem. I can find no way to resolve this, and have so far put in many hours for nothing. Please help.

Also, why is my domain not linking with the blog? Shouldn’t http://www.benbrucato.com direct to the index.php file in the root directory? It’s not, and says there is no page there. I could change that on the server side, right? But that doesn’t fix this problem I have now. As it is, I can’t access my account at all from the word press interface.