[Andreas]

In vBulletin 3.5 it's a 1 Line Plugin.
Hookname: forumdisplay_query

PHP Code:

$sqlsortfield = "(open != 0) DESC, $sqlsortfield"; 


For vBulletin 3.0
In forumdisplay.php
FIND

PHP Code:

ORDER BY sticky DESC, $sqlsortfield $sqlsortorder 


REPLACE that with

PHP Code:

ORDER BY sticky DESC, (open != 0) DESC, $sqlsortfield $sqlsortorder