disable/enable

Sure... you could reference each link by adding an "id". (see below)

<script language="javascript">
function en(str) {
var obj = document.getElementById(str)
obj.disabled = false;
obj.onclick = new Function("return true;");
}
function dis(str) {
var obj = document.getElementById(str);
obj.disabled = true;
obj.onclick = new Function("return false;");
}
</script>

<div>
<input type="button" value="enable 1" onclick="en('link1')" />
<input type="button" value="disable 1" onclick="dis('link1')" />
</div>

<div>
<input type="button" value="enable 2" onclick="en('link2')" />
<input type="button" value="disable 2" onclick="dis('link2')" />
</div>

<a href="ip.cfm" id="link1">This is my link1</a>
<a href="ip.cfm" id="link2">This is my link2</a>

You're gonna need to pass something in to identify which link.

<script language="javascript">
function en(linkId) {
var link = document.getElementById(linkId);
link.disabled = false;
link.onclick = new Function("return true;");
}
function dis(linkId) {
var link = document.getElementById(linkId);
link.disabled = true;
link.onclick = new Function("return false;");
}
</script>

<input type="button" value="enable" onclick="en('link1')" />
<input type="button" value="disable" onclick="dis('link1')" />

<a href="ip.cfm" id="link1">This is my link</a>

Is this what you were looking to do?

<script language="javascript">
function en() {
document.links[0].disabled = false;
document.links[0].onclick = new Function("return true;");
}
function dis() {
document.links[0].disabled = true;
document.links[0].onclick = new Function("return false;");
}
</script>

<input type="button" value="enable" onclick="en()" />
<input type="button" value="disable" onclick="dis()" />

<a href="ip.cfm">This is my link</a>