If the IE browser window shows a boxed section with a small 'X' icon in the upper left corner, this means the simulation can not load due to the missing Java Runtime Environment (JRE) for IE. If there is any problem with the simulation window, you will need the more current version of the Java Runtime Environment for Windows. To get the latest version for your hardware, go to java.sun.com/
link to download the Java Runtime Environment (JRE) 6. On the next page loaded, you will have to accept the licensing agreement before you can begin the download. Select SE Runtime Environment 6 for Windows Platform. This will download to your computer and automatically accessorize IE so it will open the simulations.