Naive user: Backing out of a screwed-up conversion to multi-site

THE PROBLEM:

I had a working site on my local computer. I then tried to convert it to multi-site configuration running off of a single code base (using the directions in the Drupal Cookbook for Beginners).

I ran into issues duplicating the database. After some going back-and-forth, I decided to simply go back to my initial single-site configuration.

However, the formatting of the site is now screwed up. It is as if all of the css information is gone.

SOME BACKGROUND:

I am working on Windows XP using the xampp utilities.

I think I changed (and then restored) these files.
- C:\xampp\apache\conf\httpd.conf
- C:\xampp\apache\conf\extra\httpd-vhosts.conf
- C:\WINDOWS\system32\drivers\etc\hosts

I stopped and restarted apache several times.

I don't think I changed anything inside my drupal directory (except for creating another sites subdirectory which I later deleted).

The functionality seems to be present and the data is still there. It is just an issue with the display.

THE REQUEST:

What should I do to get back to a site that displays properly?

Thanks for any pointers you could provide.

- Chip