Commentform input area issue

Try adding the code to the comment-template.php file located in wp-includes, right under the

function get_comment_author_link( $comment_ID = 0 ) {
/** @todo Only call these functions when they are needed. Include in if... else blocks */
$url    = get_comment_author_url( $comment_ID );
$author = get_comment_author( $comment_ID );

if ( empty( $url ) || 'http://' == $url )
    $return = $author;
else
    $return = "<a href="https://wordpress.stackexchange.com/questions/22734/$url" rel="external nofollow" class="url">$author</a>";
return apply_filters('get_comment_author_link', $return);
}

so that the final result looks like this:

function get_comment_author_link( $comment_ID = 0 ) {
/** @todo Only call these functions when they are needed. Include in if... else blocks */
$url    = get_comment_author_url( $comment_ID );
$author = get_comment_author( $comment_ID );

if ( empty( $url ) || 'http://' == $url )
    $return = $author;
else
    $return = "<a href="https://wordpress.stackexchange.com/questions/22734/$url" rel="external nofollow" class="url">$author</a>";
return apply_filters('get_comment_author_link', $return);
}
add_filter('pre_comment_author_url', 'filter_comment_url');
function filter_comment_url($url){
if ($url == "Website" || $url == "http://Website"){
    $url="";
}
return $url;
}