JavaScript - deshabilitar botones

<table align="right">

   <tr>

      <td>

         <input name="Aceptar Cambio" value="Aceptar Cambio" type="button" id="aceptarC" onClick="validar(document.getElementById('pres'));"/>

         <input name="Aceptar Alta" value="Aceptar Alta" type="button" id="aceptar" onClick="validar(document.getElementById('pres'));"/>

         <input name="Nuevo" value="Nuevo" id="nueva" type="button" onClick="nueva();"/>

      </td>

  </tr>

</table>

<script language="JavaScript" type="text/JavaScript">

   function nueva() {

       javascript:history.go(0);

       document.getElementById("nueva").disabled = true;

       document.getElementById("aceptar").disabled = true;

       document.getElementById("aceptarC").disabled = true;

  }

</script>

document.getElementById('nueva').setAttribute("disabled","disabled");

<input name="Nuevo" value="Nuevo" id="nueva" type="button" onClick="nueva(); return false"/>

<script">

function nueva() {

//.. tu codigo

return false;

}

</script>

document.getElementById("aceptar").disabled = true;