I've got a php website, in which i've used lots of jquery plug ins and being able to access another database for header and footer contents dynamically.Now I must give a blog that I'm checking wordpress. I'm able to produce the theme, but cannot access the header and footer dynamic contents using their company DB. Can there be another to gain access to the wordpress theme loop along with other theme functions during my simple php pages? If no then any suggestion about other simple php blog script to include within the website with Search engine optimization support please.

Thanks

You can files as you want inside a Wordpress template using include() or require(). Just place your PHP files together with your template files and you ought to be all set.

Here's the best way to forego Wordpress entirely and display something out of your old website, in case your old website now lives inside your template folder:

add_action('template_redirect', 'show_old_page');
function show_old_page() {
    if( $_GET['old_page'] == 'pagename' ) {
        include( TEMPLATE_PATH . 'oldpage.php' );
        exit;
    }
}