To check if Java is installed and enabled click on “Tools” on the IE Menu Bar and click Manage Add-ons. In the Manage Add-ons window make sure that Tool Bars and Extensions is highlighted on the left hand side of the Window and then look for the Sun Microsystems section in the main area of the window. If it is listed there but shows to be disabled, click on the Java plug-ins and enable them. If they do not show up in the Add-ins, it means that Java didn’t install correctly.
If Java was not installed correctly go to the Control Panel and uninstall java. Read this Microsoft Knowledge Base article about the Windows Installer Cleanup Utility:
http://support.microsoft.com/default.aspx?scid=kb;en-us;290301
Download and install the utility. Run it and look for the Java install and remove the leftover install files if the utility finds any. Once this has been completed follow this link to download and install Java 6:
http://www.java.com/en/download/index.jsp