Removing old Java versions
Java is notorious for installing updates (current version as of this writing is version 6, Update 23) but not removing the old versions.
Finding a system with multiple Java versions (e.g. Java 6 Update 10, Java 6 Update 17, and Java 6 Update 20 all on the system’s Add/Remove Programs) is fairly common.
Java until recently did not provide for proper “upgrading” of old versions or cleanup of them. Fortunately Java 6 Update 23 does do this properly.
To remove older versions:
It is, unfortunately, fairly primitive— simply to to Add/Remove Programs or Programs and Features and remove them one at a time by uninstalling them.