Update...
I have changed my nav code to look like this and all is good.
<ul>
<li><a href="home.php">Home</a></li>
<li><a href="help.php?section=contactus&mode=update">Cont act Us</a></li>
<li><a href="register.php">Register</a></li>
<li><a href="help.php?section=login">My Account</a></li>
</ul>
I guess I need some sleep.