We recommend that you delete any previously installed versions of the plug-in, JRE, JDK, and/or SDK before you install the new one, to avoid getting them mixed. For example, in Windows 98 you can do this by opening the Start menu and choosing Settings - Control Panel - Add/Remove Programs, then selecting from the list the items you want to uninstall. After the new installation is complete, you may need to close and restart your browser to make it recognize the new plug-in, or even reboot your computer.
Note that versions of Sun's Java above 1.3.x will not work on Windows 95.