Okay, I tried this, and it didn't work so well.
I started by going into the Style Manager, and I selected "Edit Templates". Then I drilled down to the navbar template.
I found this code, which was the only piece of code that had index.php anywhere in it:
Code:
<ul class="floatcontainer">
<li class="navbithome"><a href="index.php{vb:raw session.sessionurl_q}" accesskey="1"><img src="{vb:stylevar imgdir_misc}/navbit-home.png" alt="{vb:rawphrase home}" /></a></li>
{vb:raw navbits.breadcrumb}
{vb:raw navbits.lastelement}
</ul>
and I changed the href to the website that I want the home button to link to, but nothing happened.
What am I missing?