please download this:
http://www.java.com/en/download/manual.jsp
old windows like windows 98, or window me. download from here:
http://www.oldversion.com/Java-Platform.html
after you download and install java, restart computer and then open control panel (start button> settings>control panel)
open java panel, select 'advanced', expand default java for browsers and make sure 'mozilla family' is selected