รบกวนเรื่อง บุคคลทั่วไปมาดพสแล้วชื่อเป็นguest เคยลองถามๆในบอร์ดแล้วแต่ยัง งง เขาแนะนำ

<?php
<? session_start(); ?> <<<< ใส่ไว้บนสุดของหน้าเพจ

<?
$user=$_SESSION["username"];
if(empty($_SESSION["username"]) {
$user = "Guest"; 
} else { 
$user = $_SESSION["username"]; 
}
?> 
<?
include "connectdb.php";
include "function.php";
$id_ques=$_GET[id_ques];
//ส่วนที่1
$sql="SELECT * FROM tb_question WHERE id_ques='$id_ques'";
$result=mysql_query($sql);
$record=mysql_fetch_array($result);
$id_ques=$record[id_ques];
$title_ques=$record[title_ques];
$detail_ques=$record[detail_ques];
$name_ques=$record[name_ques];
$email_ques=$record[email_ques];
$date_ques=$record[date_ques];

$title_ques=htmlspecialchars($title_ques);
$detail_ques=wordwrap(nl2br(htmlspecialchars($detail_ques)),40,"\n",true);
$name_ques=htmlspecialchars($name_ques);
$email_ques=htmlspecialchars($email_ques);
$date_ques=displaydate($date_ques);

echo"
 <table width='480' border='1' align='center' cellpadding='0' cellspacing='0' bordercolor='#dadada' style='border-style:dotted'>
    <tr >
      <td width='480'  bgcolor='#90ccff' class='style16'><table width='480' cellspacing='0' bordercolor='#FFFFFF'>
          <tr>
            <td width='480' bgcolor='#f2f2f2' class='style16'><h3>$title_ques</h3></td>
          </tr>
          
             <tr>
            <td bgcolor='#f2f2f2' width='480' class='style16'>$detail_ques</td>
          </tr>
          
          <tr>
            <td background='images/navbar.gif' width='480' class='style14'><b class='style16'>By : </b> $name_ques   <?=$user? <<<<<<<<<<ตั้งใจจะใส่หลังชื่อคนที่มาโพสตั้งกระทู้
			<b class='style16'>Email :  </b>$email_ques   
			<b class='style16'>Date :   </b>$date_ques    
		
		</td>
          </tr>
      </table></td>
    </tr>
  </table><br>";
  
  //ส่วน2
  
  $sql="SELECT * FROM tb_answer WHERE ref_id='$id_ques' order by id_ans";
  $result=mysql_query($sql);
  while($record=mysql_fetch_array($result))  {
  	$id_ans=$record[id_ans];
	$detail_ans=$record[detail_ans];
	$name_ans=$record[name_ans];
	$email_ans=$record[email_ans];
	$date_ans=$record[date_ans];
	$ref_id=$record[ref_id];
	
	$detail_ans=wordwrap(nl2br(htmlspecialchars($detail_ans)),40,"\n",true);
	$name_ans=htmlspecialchars($name_ans);
	$email_ans=htmlspecialchars($email_ans);
	$date_ans=displaydate($date_ans);
	
	echo"
 <table width='480' border='1' align='center' cellpadding='0' cellspacing='0' bordercolor='#dadada' style='border-style:dotted'>
    <tr >
      <td width='480'  class='style16'><table width='480' cellspacing='0' bordercolor='#FFFFFF'>
         
          
             <tr>
            <td bgcolor='#ffffff' width='480'  class='style16'>$detail_ans</td>
          </tr>
          
          <tr>
            <td background='images/bg_menu.gif' class='style14' width='480'><b class='style16'>By :</b> $name_ans <?=$user?> <<<<<<<<<<ตั้งใจจะใส่หลังชื่อคนที่มาโพสตอบคำถาม
			<b class='style16'>Email :</b> $email_ans
			<b class='style16'>Date : </b> $date_ans
			
			</td>
          </tr>
      </table></td>
    </tr>
  </table><br>";
  }
  mysql_close();
  
  //ส่วนที่3
  
  
?>
<form method="post" action="answer_save.php"><center><img src='images/lineheader.gif' width='480' border='0' /></center>
  <table width="480" border="1" align="center" cellpadding="0" cellspacing="0" bordercolor="#dadada" style="border-style:dotted">
    <tr >
      <td width="480"  class="style16"><table width="480" cellspacing="0">
          <tr>
            <td height="0" colspan="2" background='images/bg_menu.gif' class="style16" style="font-size:14px">POST!!</td>
          </tr>
             <tr>
            <td width="164" align="left" valign="middle" class="style16">Detail (รายละเอียด):</td>
            <td width="332"  valign="middle"><textarea name="detail_ans" rows="5" cols="35"></textarea>
              *</td>
          </tr>
             <tr>
            <td align="left" valign="middle"  class="style16">Name (ชื่อผู้ตอบ) :</td>
            <td width="332"  valign="middle"  class="style17"><input type="text" name="name_ans" size="30" /> 
              *</td>
          </tr>
             <tr>
            <td align="left" valign="middle" class="style16">E-mail (อีเมลล์):</td>
            <td width="332"  valign="middle" class="style17"><input type="text" name="email_ans" size="30" /> 
              *</td>
          </tr>
            <tr>
           <td colspan="2" align="center" valign="middle" background='images/bg_menu.gif' ><input type="hidden" name="ref_id" value="<? echo $id_ques; ?>" /><input type="submit" value="Submit" /><input type="reset" value="Reset" /> </td>
          </tr>
          
          
      </table></td>
    </tr>
  </table>
</form>
?>

<?php
<?
session_start();
if(empty($_SESSION["name"]) {
echo "Guest";
} else { echo $_SESSION["name"]; }
?> 
?>