I was trying to compile a simple java program (Hello World) and I received this message.

C:\Users\Public\Documents\Java>javac HelloWorld.java
' javac' is not recognized as an internal or external command,
operable program or batch file.

I am using Windows 7 and I attempted to download the Java JDK 7 version.

I also cannot open the NetBeans IDE, which was downloaded along with the Java program.