Can anyone help me with java?

[dags]

When i enter chat rooms etc. A pop up menu appears telling me java is not installed or not responding. Java is still in my computer. I try-ed to download a update but that didn't work. As its my first computer i haven't a clue how to reinstall java. Its a Mac book os x 10.5 , 2 ghz intel.

[Muff]

try this, its a browser plug in.