There are several updates from Microsoft for Windows, Internet Explorer and .Net. Oracle has updates for both Java versions 6 and 7. Last but not least Adobe has updates for Flash Player. You can find links for all of these on the side or use the update features.
Edit: It appears that if you have Java 6 installed and you use the updater it will update you to version 7. If for some reason you need to stay on version 6 you can find the update at http://www.java.com/en/download/manual_v6.jsp
