i have never been able to get javac to work on any of my own computers in 3 years of (limited) java programming.
Let me get this straight: you've been programming in Java for 3 years, but not ONCE have you ever compiled any of the code that you have written?

Invest in reading up about some of the IDE's (Integrated Development Environment) such as Eclipse (my personal free favorite) or Netbeans. Also, now days if you install the SDK and JRE from Sun and install Eclipse, you shouldn't have to do anything with the classpath. At least I haven't had to mess with the classpath (for general running of Java) in a long time.