if(isset($_POST['send'])){
$name = $_POST['name'];
mysql_connect(...................) or die(mysql_error());
mysql_select_db(...............) or die(mysql_error());
$query = mysql_query("UPDATE users SET fsk=fsk-100, SET nrg=nrg+100 WHERE name='$name'") or die(mysql_error());
if($query){
echo "Успешно";
} else {
echo "error";
}
} else {
<form method="post" action="">
<input type="text" name="name" /><br />
<input type="submit" name="send" value="Промени" />
</form>
}