What is the error that you get with Java?
Once the .MSI files are gone, they are gone. This usually occurs by using a program such as JavaRA, or Windows Installer Cleanup Utility. THe .MSI files are the installer packages for the products in question. Once they are gone the product is not going to be able to be uninstalled.
Therefore, your only option at this point is to attempt to reinstall each product in question using the exact version that you are trying to get rid of. In other words, try re-installing OpenOffice 2.3. And then uninstalling it normally through add/remove programs. Try installing Java 6 update 7 and then uninstall it normally through add/remove prorgams.
However, I'm not sure where you can get the OpenOffice 2.3 installation file from any more. Older versions of Java can be downloaded from here: http://java.sun.com/products/archive/
You want the JDK/JRE 6 update 7: http://java.sun.com/.../6u7/index.html
You can try here for the 2.3.0 of OpenOffice: http://www.filehippo...penoffice/3193/
Problem is, there is also a 2.3.1 version and you should know which one you have and use that exact version. The 2.3.1 version is also available on filehippo.
Once the products are uninstalled properly, then you can download and install the newest version of each.
Let us know what you come up with and the exact error messages and procedures you followed if there is a problem.