Change the search query in customer/search.php from the one I qouted above to:
Code:
$search_query = "($sql_tbl[products].product like '%$substring%' or $sql_tbl[products].descr like '%$substring%' or $sql_tbl[products].fulldescr like '%$substring%') and $sql_tbl[categories].category like '$search_category%' and $sql_tbl[products].forsale='Y' and $sql_tbl[categories].avail='Y' $price_condition ";
that'll do it