Once the newest Java is installed, you will need to create security exceptions in order to run unsigned programs. Here's how to do that on Windows 8:
- First, try to launch the app or website in question. You will likely find the window below; take note of the address in the Location field.
- Click OK, and close the browser.
Do a search (swipe in from the right side of the screen, then choose Search) on your computer for "java" and one of the first options should be "Configure Java." Click that.
- Go to the "Security" tab.
- Near the bottom, click "Edit Site List."
- Click "Add" in the Exception Site List window.
- Enter (or paste) the Location address (noted in the first step) in the new site field. Hit Enter, then click "Continue."
- Click OK then OK then OK to get out of the Java window.
Now, try to reload the site. You'll probably get a "Plug-in Blocked" message near the top right of the browser window; click that message, and choose "Allow." If you get another Java pop-up, click "Allow" or "Run" there, as well.