Here, try this.
create a new text file using Notepad++ and copy and paste this bit of code inside it:
Code:
<?php
header( 'Location: http://www.yoursite.com/new_page.html' ) ;
?>
Change the text in red to your new subdomain, and save the file as "index.php". Put the index file inside old.com/vb.
Now when people go to old.com/vb, they will be redirected to your new subdomain.
You could also do this in your Domain DNS Settings, or with htaccess. The option I showed you is the easiest way.