Installing and upgrading help

I'm attempting to upgrade my moodle site to 1.5. I've uploaded all the files minus the languages and templates I don't want to use.

When I begin the installation process I get a screen that asks me to select a language. In the lower right hand corner is a text reading "language". However, there is nothing to select.

What am I missing?

Also, I'd like to make a clean installation rather than using my curing config.php file. If I go this way, will the install process wipe out my current db data? (I've made a backup in case).

Thanks,
Matt