you got classpath problems ...
read java  / sun manual about setting classpath ...:)
(in installation manual)

This is the most common exception  for the new java  developers. Your
current path is not defined in class  path variable so thats why the
error comes. Please type the following line at prompt before running
your program

SET CLASSPATH=%CLASSPATH%;\.

here I typed the dot means your current directory on the classpath
now and now your class is on the path run it and enjoy.

Let me know, is you problem resolved??

If your javac  command (the line that read "javac hello.java") compiled  the
source code with no errors, then
a file named hello.class was created in the directory you ran it from.

If the java  command (the line that read "java hello") gives the error you
mention, it means that the java executable can not find the file hello.class.

Running the command "set" will reveal if you have a CLASSPATH environment
variable set and what it is set to.

You can also specify a classpath when you run the java executable with a
classpath switch in several ways:

java -classpath "C:\" hello

or

java -classpath %CLASSPATH%;"." hello

I am interested in learning java  programming from now starting at
beginner`s level.
Would anyone out there please help me on what will be the better ways
of learning it.
Up to now i only have basic skills in pascal programming and i am not
sure whether it will help in anyway or i need some other skills before
attempting java lessons.

You don't need anything special. You will just need to learn OO programming.
The best thing to do is to actual program, not read books