Update.
I went to the Java.com site took a deep breath and downloaded update 20.It installed ok.The UAC screen opened and said a programme needs my permission to continue,(Java Auto Updater)I clicked continue and it installed ok.
I then opened the Java control panel and clicked on 'update now'Instead of getting the error screen it took me to the darkened UAC screen and said that a programme needs etc,etc,so it seems to have worked
The only problem I have now,and I did have before is that when I open the Java Control Panel>update> advanced.I then change the date and time of the check for updates,click ok.It then shows me the date and time I have changed it to,so I click on 'apply' and close the control panel.
Trouble is when I open it again it has reverted back to the original date and time.
I know this not a big problem,its just bugging me thats all