I do a couple of things before installing a new Java. First;
uninstall the old one, reboot
Go here and download "JavaRA" which helps uninstall left over items of Java
JavaRa | Free System Administration software downloads at SourceForge.net
Put on desktop
Run the program. Then after running the program, I use Ccleaner to clean up left overs.
Also, do a search of your hard drive for "Java" and you will still find left overs.
Reboot again.
Just like LayBack Bear says, then go to the Java website, download the one you need and then install. Then reboot and make any necessary settings adjustments.