1. In the HEAD of the document:

<SCRIPT LANGUAGE="JavaScript">

function Disab (val) {
if(val=="1")
{form1.gr11[0].disabled=false;
form1.gr11[1].disabled=false;
form1.gr12[0].disabled=true;form1.gr12[0].checked=false;
form1.gr12[1].disabled=true;form1.gr12[1].checked=false}
if(val=="2")
{form1.gr11[0].disabled=true;form1.gr11[0].checked=false;
form1.gr11[1].disabled=true;form1.gr11[1].checked=false;
form1.gr12[0].disabled=false;
form1.gr12[1].disabled=false}
}
</SCRIPT>

2. In the BODY:

<form name="form1" method="post" action="">
<input type="radio" name="gr1" value="Yes" onClick="Disab
(1)">
<input type="radio" name="gr11" value="Yes" disabled>
<input type="radio" name="gr11" value="No" disabled>
<BR><BR>
<input type="radio" name="gr1" value="No" onClick="Disab
(2)">
<input type="radio" name="gr12" value="Yes" disabled>
<input type="radio" name="gr12" value="No" disabled>
</form>