Yep, you can change the href of a link, and yes you can disable the link then by changing the href to:
href="javascript:void(0)"
which does nothing, and is better than "#" because it doe not make the page jump up to the top.
So all you do is reference the link by giving it an ID:
<a href="somePage.html" ID="myLink">
then you can access it from:
document.all['myLink']
Then just access href in the usual way:
onClick="document.all['myLink'].href='newHref.htm'"
where new href may be javascript:void(0) for nothing to happen. I think this is the most straight forward way to do this. As I recall perhaps using the document.all array isthe only way to access links, apart from links array.
hope this helps! BEN.