[Adrian Schneider]

Try using a sub-query like this,

PHP Code:

$twentyfourago= TIMENOW - 86400;

$result = $db->query_read("
    SELECT *
    FROM (
        SELECT *
        FROM " . TABLE_PREFIX . "thread
        WHERE dateline >= $twentyfourago
        ORDER BY replycount DESC
        LIMIT 7
    ) as sub_results
    ORDER BY dateline DESC
");

$populardisplay = '';
while ($thread = $db->fetch_array($result))
{
    $populardisplay .= "<b><a href=\"showthread.php?t=$thread[threadid]\">$thread[title]</a></b>
        <br /><span class='smallfont'>&nbsp;     &nbsp;by
        <a href=\"http://www.nwfans.com/member.php?u=$thread[postuserid]\">$thread[postusername]</a> </span><br />";
} 


Another idea is to do it in PHP using array sorting.