I just downloaded OpenOffice.org 2.4. I have a book that incl. a CD w/OOo 2, Firefox & Thunderbird.?

Which version is the most current? Should I uninstall the 2.4 version that I downloaded directly from the site and use the CD with Firefox and Thunderbird? By the way, I'm not familiar with either Firefox or Thunderbird, so any pointers and pro/cons would help. Will having Firefox and Thunderbird on my computer interfere with my Internet Explorer and Yahoo mail? I'm running Windows 2000, if it matters.