Could not find or load main class

Question

I have Windows 7, installed jdk1.7.0 and its supporting jre7.
My problem is compilation part works perfectly, but while running the Java program I get this error saying:

Answer 1

You might have the CLASSPATH environment variable already added!!

Use following to avoid further usage of -cp . in java -cp . CLASSFILE

Add . to CLASSPATH in system properties->environment variables or by cmd

set CLASSPATH=%CLASSPATH%;.;