Hoffaz,
How do I enable Java through the Control Panel :
https://www.java.com/en/download/help/enable_panel.xml
How do I clear the Java cache:
https://www.java.com/en/download/help/plugin_cache.xml
If the above mentioned jobs fail follow the final resource as mentioned below.
Delete your JRE on your client system and install corresponding versions of the JRE
Java Runtime Environment.
..........
Mutti