Hi,
Welcome to JavaRanch!
Do not post the same question to more than one forum. See
here for some reasons why. I've deleted all the other copies.
This is not really a Java question, but an OS question: sometimes your browser crashes when viewing Java applets. The answer is to upgrade your browser, OS, video drivers, Java Plug-in, etc, with all the latest patches. By definition, a Java program can't crash your browser. Any time it does, it's a bug in one of the above. Nothing you do in Java can change that.