start menu -> control panel -> add or remove programs -> ensure "show update" is checked at top center of window. locate "Java(TM) Update 20" and select remove.
If you do not have the earlier versions of Java installed you will have to go to their website, and get it.
When a Java tries to update a little orange icon will appear on your toolbar near the clock. Right click on it, and you should be able to find outupdate options there.
Use this link to get whatever version of Java you need...if necessary:
http://java.sun.com/products/archive/Hope that helps
FDM