Unless any body wishes to correct me, I'd have thought Java is one of those things that needs to be installed onto the C drive. At least, it is generally best not to have more than one version of Java installed on your system (64/32 bit java 'might' be an exception where you are only using the 32 bit browser). Thus, I'd suggest you download the 'Offline' version of Java. Then uninstall the Javas listed in the Add/Remove Prog. Control Panel. Then install the Offline version you downloaded. Then reboot computer. Hopefully that will fix the issue. Perhaps look at this technique (to be sure the system is clean & no remnants of other java remain):
http://www.gnutellaforums.com/333278-post2.html