If you are using Windows XP and have trouble viewing equations, the Chat, or the Virtual Classroom in your course, you may need to update your system software and install the Java plug-in.
To check the version of Windows on your computer, select Start > Control Panel. From the Help menu, select About Windows.
Try these troubleshooting tips:
Install the latest service packs for Windows XP from http://windowsupdate.microsoft.com.