While removing another program through Add and Remove on the Control Panel I realised that I have three different entries related to Java:

J2SE Runtime Environment 5.0, update 11
Java 2 Runtime Environment SEv1.1.2_13
Java SE Runtime Environment 6, update 1.

I know that I need JRE to run the Open Office suite, but other than that I'm not sure. The computer hasn't been noticeably weird but still I wonder if any of these can be safely removed.

Thanks.

The latest is Java 6 Update 2.

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

All previous versions can be removed.

Forgot to mention: Choose Custom Install and remove all the garbage such as language packs and Google Toolbar etc.

Thanks again Jephree.
Looking forward to receipt of your manuscript. Maybe you could send the first 500 pages in advance?