Theme doesn’t appear to load when activated

The theme was working, but then I changed to a couple of themes for the fun of it, and then changed back and the theme no longer appears to load.

The data pulls up out of the database, what little there is at this point, but it’s all in a left justified column like there is no theme at all present. It’s like when you click on a web page, but it doesn’t load properly.

I’m testing out themes for the intranet for a nonprofit so I can’t post a like to the site to show anyone what it actually looks like.

The other two themes I tested where:
Magazine Basic 2.6.1
WP-Creativix 1.5.5

I’m guessing one of them had a conflicting feature?

I was in WordPress 2.9.2, but upgraded to 3.0 as if that would help, which it didn’t.

I did not have the theme active while I did the upgrade, and had all plugins deactivated.