Try the following, and let me know exactly what it's doing or not doing...
// First check to see if the page variable is set.
if (isset($_GET['page'])):
// If the variable is set, then check to see if the value is main.
if ($page = 'main'):
// This is included if the page is the main page.
include ("includes/powcount.php");
else:
// Put an include here if you want if the page is not the main page.
endif;
else:
// Put something here if the variable is not set.
endif;
Note, I use a slightly different convention for my if else statements. I think it is easier to keep track of things when you use the colons and semi-colons, and put in the necessary else and endif statements. If you want it your way, then take out the colons, semi-colons and unneeded conditional statements, and put in your brackets...