This is a Java installation problem rather than a JACK® one. It sounds like your old Java xxx runtime or JDK has become stuck in the registry. Possibly the previous Java that was installed did not get uninstalled properly and now there are incompatible Java components mentioned in the registry.
Although tedious, we suggest the following:
- Uninstall all Java or JDK software (via Control Panel).
- Make sure all Java or JDK software are actually removed. (E.g. delete the C:\Software\JavaSoft folder if it exists and the JDK folder, wherever you installed it)
- Search the registry for any key or value containing "java" and remove it! (Use the "Run..." command and type 'regedit', then use the find command within regedit)
- Install the new JDK again.
- Make sure you have PATH & CLASSPATH set properly. Check that the "BIN" directory of the JDK is in your PATH since the Java installer does not seem to do this for you.