In "Add/Remove Programs" I see I've got the following Java software installed:

J2SE Runtime Environment 5.0 Update 6 (119MB)
Java 2 Runtime Environment SE v. 1.4.2_01 (136MB)

Also, when I click on Tools in Internet Explorer, included in the dropdown is Sun Java Console.
When I click on that, a box appears informing me that it's a Java Plug-in 1.5.0_06 with a list of "commands".

As you can spot, I'm a computer novice but I would like to know whether I need any or all of the above.

Your expert advice is awaited.

Hi Jamjar

You can remove this one from the Add/Remove screen :

Java 2 Runtime Environment SE v. 1.4.2_01 (136MB)

The above version is out of date and some older versions are being exploited by Malware writers, Trojan Vundo is one infection that takes advantage of older versions to infect the system so its worth removing it from the pc, you do have the latest Java installed which is Java Runtime Version 1.5.0_06 so you do not need to upgrade after removing the old Java entry,

After removing the 1.4.2_01 Java version from the Add/Remove screen you can check that you have the latest Java installed by visiting this link

http://www.java.com/en/download/installed.jsp

Thanks Andy

This is a very responsive forum.

I dont have any Sun Java stuff installed.

#1 Update 6 is the latest.

#2 You can also open Control Panel -> Java -> Update tab -> "Update Now" button to check the latest version. The method didn't work prior to Update 5, but I've upgraded from Update 5 to Update 6 this way.

In earlier versions of the Java RTE, multiple versions may have been needed for different Java applications; this is why previous versions were not uninstalled when you installed the latest update.

With 1.5_06, as well as 1.6 (currently in beta), earlier versions are no longer needed; they now contain everything in one.