in include/client/open.inc.php
<select name="topicId">
<option value="" selected >Select One</option>
<?
$services= db_query('SELECT topic_id,topic FROM '.TOPIC_TABLE.' WHERE isactive=1 ORDER BY topic');
if($services && db_num_rows($services)) {
while (list($topicId,$topic) = db_fetch_row($services)){
$selected = ($info==$topicId)?'selected':''; ?>
<option value="<?=$topicId?>"<?=$selected?>><?=$topic?></option>
<?
}
}else{?>
<option value="0" >General Inquiry</option>
<?}?>
</select>
to:
<input type="hidden" name="topicId" value="HELP_TOPIC_ID">
Replacing HELP_TOPIC_ID with the ID of the help topic you want to use.