Open up template-functions-post.php, which can be found under the wp-includes directory, in any text editor and find the following line (should be around line 98).

$output .= ' < a href="'. get_permalink() . "#more-$id">$more_link_text";

Change this line to:

$output .= ' < a href="'. get_permalink() . "">$more_link_text";

Save the file, upload and voila.