You can remove it from the core file. Look for footer.php and then search for Powered by CTR theme word, remove the text with anchor tag and your problem would be solved.
Basically what he said. Go to wp-content -> themes -> your theme. There look for the file named footer.php; it could be in a lib folder.
Good luck.
if you can't edit a wordpress footer you gotta ask yourself "Is IM really for me?"
people out there need dishes washed and holes dug all the time
Actually laughed out loud at the part in bold!. As others have said you should be able to remove it from the themes options. If not edit the footer.php file, it should be in there.
As partymarty said, if you can't figure out how to do basic WP editing on your own, you should question if IM is for you. - That's not a dig, just being honest.
<?php
/**
* The template for displaying the footer.
*
* @package WordPress
* @subpackage CTR Theme
* @since CTR Theme 1.0
*/
global $subtheme_dir;
include($subtheme_dir . 'footer.php');
wp_footer();
?>
</body>
</html>