You could try uninstalling ALL of the current Java editions on your system, including the 64-bit version, and try re-installing them all once again. Since you're running Windows, you can just click on the "Free Java Download" on THIS PAGE
and it will install the latest version.
You can find the 64-bit version ♠ HERE
. You'll also notice at the top of this page a link that says "Remove Older Versions." If you click on that link, it will take you to a page explaining what you can do to uninstall the older versions.