Within the theme's root directory their should be a style.css file. It should look similar to this:
Theme Name: My Theme
Theme URI: http://wordpress.com
Description: A WordPress theme designed by me.
Tags: what, ever, you, want
Also, I was able to change the directory name but it was kind of tricky...lets say you are modifying THEME-A and you want to call it EDIABLO7. Download THEME-A onto your personal PC. Uninstall the THEME-A from WordPress and install EDIABLO7. If you simply just rename it without re-uploading it, it doesn't work (well, at least for me!)