ช่วยดูโค๊ดให้หน่อยค่ะ มันแก้ไข้ข้อมูลไม่ได้นั้งงงมาสองวันแล้ว

<?php
function back() {
 	mysql_close();
	echo "<p /><a href=\"reportprinter.php\">ดูรายการทั้งหมด</a></body></html>";
	exit;
}
include("Connections/docconnection.php");

$tb="printer_profile";

if(isset($_POST['printer_ID'])) {


	unset($_POST['Submit']);

$values = implode("', '", $_POST);
	
	
	$values = "'" . $values . "'";
	

	$sql = "REPLACE INTO printer_profile VALUES($values);";
	
	$result = mysql_query($sql);
	if(!$result) {
		echo mysql_error();
	}
	else {
		echo "ข้อมูลถูกบันทึกแล้ว";
		back();
	}
}



$printer_ID = ""; $com_name=""; $printer_brand=""; $printer_model=""; $printer_serial=""; $printer_purchase=""; $printer_status=""; 

if(isset($_GET['action'])) {
	$action = $_GET['action'];

	if($action == "insert") {
		echo ">> เพิ่มข้อมูล";
	}
	else {
		$printer_ID = $_GET['printer_ID'];
		
	
		if($action == "delete") {
			$delete = mysql_query("DELETE FROM printer_profile WHERE printer_ID = $printer_ID;");
			if(!$delete) {
				echo mysql_error();
			}
			else {
				echo "ข้อมูลถูกลบแล้ว";
			}
 			back();
		}
		else if($action == "update") {	
			echo "";
			$result = mysql_query("SELECT * FROM printer_profile WHERE printer_ID = $printer_ID;");
			list($printer_ID, $com_name, $printer_brand, $printer_model, $printer_serial,  $printer_purchase, $printer_status) = mysql_fetch_row($result);
		}
	}
}



mysql_close();
?>
		 <td width="773" height="21" align="center" valign="top">
           <form name="form1" method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">
            <table width="590" height="430" border="0" cellspacing="0" cellpadding="0">
              <tr>
                <td align="center" valign="middle" background="img/images/bgad.jpg"><table width="550" border="0">
                  <tr>
                    <td width="139"><span class="style4">printer_ID</span></td>
                    <td width="269"><span class="style4"><?php echo $printer_ID; ?>
					<input name="printer_ID" type="hidden" size="11" value="<?php echo $printer_ID;?>" /></span></td>
                  </tr>
                  <tr>
                    <td><span class="style4">com_name</span></td>
                    <td><select name="com_name" size="1" class="Txttext" id="com_name" style="width:200px">
                        <option value="" selected="selected">- <?php echo $com_name; ?>-</option>
                        <?php
include("Connections/docconnection.php");
 
$objDB = mysql_select_db("notebook");
$strSQL = "SELECT com_name FROM com_profile";
$objQuery = mysql_query($strSQL) or die ("Error Query [".$strSQL."]");
while($rs=mysql_fetch_array($objQuery)){
echo "<option value>" . $rs["com_name"] . "</option>";
}
?>
                      </select>                    </td>
                  </tr>
                  <tr>
                    <td><span class="style4">printer_brand</span></td>
                    <td><input name="printer_brand" type="text" value="<?php echo $printer_brand; ?>" size="30" /></td>
                  </tr>
                  <tr>
                    <td><span class="style4">printer_model</span></td>
                    <td><input name="printer_model" type="text" value="<?php echo $printer_model; ?>" size="30" /></td>
                  </tr>
                  <tr>
                    <td><span class="style4">printer_serial</span></td>
                    <td><input name="printer_serial" type="text" value="<?php echo $printer_serial; ?>" size="30" /></td>
                  </tr>
                  <tr>
                    <td><span class="style4">printer_purchase</span></td>
                    <td><input name="printer_purchase" type="text" value="<?php echo $printer_purchase; ?>" size="30" /></td>
                  </tr>
  <td><span class="style4">printer_status</span></td>
      <td><input name="printer_status" type="text" value="<?php echo $printer_status; ?>"  size="30" /></td>
  </tr>
                </table>
                  
                  <table width="117" height="80" border="0">
                      <tr>
                        
                        <td width="55"><input name="Submit" type="submit" value="ตกลง" /></td>
						 <td width="332" align="center" valign="top"><input name="reset" type="reset" id="reset" value="ยกเลิก" /></td>
                      </tr>
                      <tr>                      </tr>
                    <tr> </tr>
                    <td><a href="reportprinter.php" class="style1"><br />
                    </a></td>
                    </tr><tr>
                      <td>&nbsp;</td>
                    </tr>
                    </table>
                  
          </form>        
					
		
<body>
</body>
</html>