I was running out of space on my laptop's system drive so I started deleting trash left over by programs long gone.  When I looked inside my user account folder within the idiotically named "Documents and Settings" folder, I was surprised to find several complete copies of JDK and JRE installer files (MSI).  I am not sure why they were there but wiping them out saved me quite a lot of space.  If you installed JDK or JRE on your system, take a look inside:

> %SystemDrive%
    Documents and Settings
      %USERDOMAIN%.%USERNAME%
        Local Settings
          Application Data

Folders containing the copies have OLE GUID names like {ABCD-1234-ABCD-1234}.