Computer Systems: Settings:
Operating System?
Cookies Enabled?
Active X Enabled?
Java Installed?
Quicktime Player Installed?
Flash Plugin Installed?
Shockwave Plugin Installed?
RealPlayer Installed?
Silverlight Installed?
Windows Media Player Installed?
Adobe Reader Installed?

Be sure that you have the latest version of Adobe Acrobat Reader (not all classes require).

Not all components are required for all classes.