ragazzi questo è il codice delle 2 pagine:

la prima pagina è valida_servizi.php:

Codice PHP:
<?php 
include ("checkuser.php");
?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>Virtual Credits - home</title>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1">
<meta name="generator" content="HAPedit 3.0">
<style type="text/css" media="screen">
@import "css/stile.css";
</style>
</head>
<body>
<div id="container">
  <div id="header">  
  </div>
  <a name="val"></a>
  <div id="navigatione">
        <h3>[img]icons/user.png[/img] logged as <?php echo $_SESSION["admin"]; echo " - your V.O. is ", $_SESSION["vir_org"]; echo " - latest access ", @$_SESSION["vecchia"]?></h3>         
  </div>
    <div id="content">
      <div class="textimage">
            <h2> Services validation </h2>
            

             


            <?php
            /* Connessione e selezione del database */
            $connessione = mysql_connect("localhost", "root", "")  or die (
            "Connection refused: " . mysql_error());
    
            mysql_select_db('crediti');
    
            $query = "SELECT servizio.nome, servizio.data, servizio.nome_lab FROM servizio WHERE servizio.validazione = '0' AND servizio.nome_vo = '".$_SESSION["vir_org"]."'";

            $result = mysql_query($query, $connessione) or die("nessun risultato" . mysql_error());
            $tuple = mysql_num_rows ($result);
            
            //echo "You have [b]$tuple[/b] validate messages";
            
            if(mysql_num_rows ($result) > 0)
            {
            echo "<form action='scelta_val.php' method='post' name='scelta'>";
            echo"<table width='100%' border='0'>";
            echo "<tr><th align=\"center\"></th><th align=\"center\">Name</th><th align=\"center\">Date</th><th align=\"center\">Laboratory</th></tr>";
                
            while($ris = mysql_fetch_array($result))
            {
                $nome = $ris["nome"];
                $data = $ris["data"];
                $lab = $ris["nome_lab"];
                
                echo
                "<tr>
                <td><div align='center'><input name='checkbox[$nome];' type='checkbox' value='$lab'></div></td>
                <td><div align='center'><a href='prova.php?nome=<?=$nome?>' class='top'>$nome</div></td>
                <td><div align='center'>$data</div></td>
                <td><div align='center'>$lab</div></td>
                </tr>";
            }
        
            echo"</table>

";
            echo "<p class='submit' align='right'><input name='validate' type='submit'  value='Validate' /><input name='not_validate' type='submit'  value='Not validate' /></p>";
            echo "</form>";
            
            if (isset ($_REQUEST["up"])) 
                { 
                  //echo "[b]session elapsed or user unknown[/b]";
                echo "<script type='text/javascript' language='JavaScrip'>var oggetto = new Object();
                                    oggetto.testo = 'Validation complete';
                                    oggetto.funzione = function() {
                                      alert(oggetto.testo);
                                    };
                                    setTimeout(oggetto.funzione, 150);
                                </script>";
                }
                else if (isset ($_REQUEST["down"])) 
                { 
                  //echo "[b]session elapsed or user unknown[/b]";
                echo "<script type='text/javascript' language='JavaScrip'>var oggetto = new Object();
                                    oggetto.testo = 'Please choose an element';
                                    oggetto.funzione = function() {
                                      alert(oggetto.testo);
                                    };
                                    setTimeout(oggetto.funzione, 150);
                                </script>";
                }
                }
            ?>
          </p>
      </div>
      <div class="textimage">
          <a name="val">
        <?php
        
        if($nome <> NULL)
        {
            //echo $_SESSION["nome"];
        }
        
        ?>
        </a>
      </div>      
  </div>
    <div id="extra">
        <div class="newsbox">
            <h2>Documentation</h2>
            

[img]icons/page_white_acrobat.png[/img]Download
              official documentation in pdf format </p>
        </div>
        <div class="newsbox">
            <h2>Job statistic </h2>
            

[img]icons/statistic.png[/img]View
              the Grid statistic (update every 108 minutes) </p>
        </div>
        <div class="newsbox">
            <h2>Link</h2>

            <div align="center">[img]images/egee_logo_blue_bg.gif[/img]
              <map name="Map">
                <area shape="rect" coords="0,1,103,52" href="#">
              </map>
            </div>
            

            <div align="center">[img]images/infngridlogo.jpg[/img]
              <map name="Map2">
                <area shape="rect" coords="1,0,108,52" href="#">
              </map>
            </div>
        </div>
  </div>
    <div id="navigation">
        <ul id="navigazione">
            <li id="home">[url="home.php"]Home[/url]
            <li id="laboratory">[url="laboratorio.php"]Laboratories[/url]
            <li id="superuser">[url="membro.php"]Superuser[/url]
            <li id="credits">[url="credito.php"]Credits[/url]
            <li id="logout">[url="logout.php"]Logout[/url]
        [/list]
  </div>
    <div id="footer">---</div>
</div>
</body>
</html>
la seconda pagina è prova.php

Codice PHP:
<?php
// inizio sessione
    session_start ();
    
    echo $_GET["nome"];
?>
come vedete nella pagina prova.php ho inserito $_GET["nome"] ma nonfunziona niente..

come devo fare??

ciao