Enable Java?

I am trying to access my Jobs secure website remotely but can't do it. As of last week I was able to log in from home without problems and finishe my work. Now whenever I log in and try to open the application the message "your computer must enable Java" appears and can't open it. How do I enable Java? Why wasn't I having this problem before? The only thing that has changed is that my work did an upgrade on their software but that should not affect my computer settings. Ami I correct?