Ok, since your using the command prompt I can help you even more, because that's what I use. First of all, you need to create a folder on the C drive, and name it whatever you want. This is the folder you'll put all of your source files, class files, and miscelaneous files in.

Now to the environment variables:

Considering you have windows:

Goto start--->right click on my computer--->select properties
Goto the advanced tab, and you should see a button at the bottom that says environment variables...click on that.

The only thing you need to worry about is the PATH variable, and the CLASSPATH variable, nothing else.

SKIP THIS STEP AND GO ON TO THE CLASSPATH, IF IT DOESN'T WORK AFTER SETTING THE CLASSPATH, THEN COME BACK AND SET THIS.
The path variable must point to the bin folder in the sun app server, and the bin folder in the jdk directory. Now, those are two different directories, so you seperate them with a semicolon when creating it. Here is what mine looks like:

C:\Sun\AppServer\bin;C:\Program Files\Java\jdk1.5.0\bin




Classpath....This points to the tools.jar file in the jdk directory. It's pretty easy to find. Here is what mine looks like:

.;%classpath%.;C\Program Files\Java\jdk1.5.0\lib\tools.jar

Your's will look similar, although you do not need the .;%classpath%.; statement.


Next, you need to know how to access your files at the command line.

To do so, you simply type cd/folderName at the command line. The cd stands for current directory. My folder was named javawork, so to access it, I did this at the command prompt:

cd/javawork // brings me to the right directory
javac Hello.java //compiles my program
java Hello //runs my program


Let me know if you don't undestand something or need more help.