I have installed Firefox and the latest (and compatible) Java and Java Script on a PC and a laptop. They now display web pages slightly differently. And, on the laptop, under Tools/Options/Contents I have four boxes to tick (including "Enable Java"). On the PC I only have three boxes to tick; the "Enable Java" is missing. The version of Java is verified. On the PC, the Plugins on Add-ons show that Java is there and enabled. I have tried re-installing Firefox. I have tried re-installying Java. What is happening?