Don,
This works as you asked in IE5(NT4/Win95,98,2000) and Netscape 4.72(Win95/NT4)
Hope this helps
-pete
<SCRIPT LANGUAGE="JavaScript">
<!--
function checkBoxChange( oThis){
// if All is not clicked and checked
if ( 0 != oThis.name.indexOf("All"

&& oThis.checked){
document.form1.All.checked = false;
// else if it is 'All' and it is checked
}else if ( 0 == oThis.name.indexOf("All"

&& oThis.checked){
document.form1.Red.checked = false;
document.form1.Green.checked = false;
document.form1.Blue.checked = false;
}
}
-->
</SCRIPT>
</HEAD>
<BODY>
<FORM NAME="form1">
All: <input name="All" type="checkbox" value="0" onclick="checkBoxChange(this)"><br>
Red: <input name="Red" type="checkbox" value="1" onclick="checkBoxChange(this)"><br>
Green: <input name="Green" type="checkbox" value="0" onclick="checkBoxChange(this)"><br>
Blue: <input name="Blue" type="checkbox" value="3" onclick="checkBoxChange(this)"><br>
</FORM>