New to Java

I installed jdk 1.5 on my windows XP SP2 system and tried to run a simple program:

public class Hello {
	public static void main(String[] args) {
		System.out.println("Hello world!!");
	}
}	

but i get the following error:
Exception in thread "main" java.lang.NoClassDefFoundError: Hello/java

I've set the classpath as:
CLASSPATH=C:\Java\jdk1.5.0_09\lib;

and path variableas:
%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\system32\WBEM;%SYSTEMROOT%\system32\WBEMC:\PROGRA~1\COMMON~1\AUTODE~1;C:\Java\jdk1.5.0_09\bin;c:\j2sdkee1.3.1\bin;c:\Java\jdk1.5.0_09\lib;

I didn't have this problem when i was using SP1 of windows xp...
Plz help!!