GREAT... it worked!
For those neophytes out there (like me), I'll explain the steps I took so that it may help others...
1. I learned that as Richard mentioned, I need to use Notepad to edit the pages.
2. Downloaded FileZilla (free ftp program suggested by WordPress) so I could transfer files via FTP.
3. Learned that the appropriate file to modify is the Header.php file located in the theme folder in the directory. I downloaded a copy of this file as back-up. In my case, this file is located at Blog/wp-content/themes/default/
4. Within the Header.php file I found the following script and highlighted the text...
<div id="header">
<div id="headerimg">
<h1><a href="<?php echo get_settings('home'); ?>/"><?php bloginfo('name'); ?></a></h1>
<div class="description"><?php bloginfo('description'); ?></div>
5. Cut the highlighted text and replaced with the following...
<div id="header"onclick="location.href='http://MY URL;" style="cursor: pointer;">
<div id="headerimg"></div>
6. Uploaded the changes and tested.
This works great! I don't know how it works but it does. My whole header image is a hyperlink to the main page. My suggestion to WordPress is to make this much more intuitive by allowing an option in the admin option page to allow the header to be a hyperlink rather than the title.
Thanks for your help!