Sometimes people using Windows Internet Explorer have problems with new Windows updates adding in extra security patches which block the Javascript content. Clicking on the yellow strip at the top of the screen will let you allow blocked content which should display the files perfectly. If you continue to have problems, try using Mozilla Firefox, which is another (free) web browser.
A few of the revision tasks require Macromedia Flash to run. This is a common plug-in that many people will already have installed on their computers. If you do not have Flash installed, an error message will pop up when you attempt to run these files. Download the latest version of Flash here. A version of Flash that will work on most Windows machines is found in the Software folder.
If you cannot view the PowerPoint shows, click here for information on installing PowerPoint Viewer. This file also contains instructions for using PowerPoint.
Some people find that the animations do not display correctly when using older machines or alternatives to Office. In these cases, try viewing the files with PowerPoint Viewer. To do this, right click on the show in the PowerPoint folder, select Open with..., and choose PowerPoint viewer (which you may need to install first). If the animations do play correctly with the Viewer, then tick the option in the Open with... and Choose program... menu that says "Always use selected program to open this kind of file."
You will also need software to play the movies in the Organic PowerPoint files. Versions of Windows Media Player (which will play these movies) for various operating systems (both PC and Mac) can be downloaded from here.