We had this same problem; after much durm and strang we found a fix that worked across all our computers:
Go to Java - LEFT hand side of the page has an option, "Download offline"
Download java OFFLINE
Reinstall Java
Go to "Configure Java" from your start menu
Choose "Security" from the top menu tabs
Choose 'Edit List" about half way down the page
Click "Add" then ADD YOUR SITE to the list
Hit save
It will all work.
It's a miracle.