1).Click on C: drive >> program files >> java >> jdk >> and finally bin...
Copy this complete directory
e.g. C:\Program Files (x86)\Java\jdk1.7.0\bin
NOW
Right click on My Computer, click properties
Click on "Advanced system settings"
Click on "Advanced"
Click on "Environment Variables"
Single Click on "path" and than click "Edit"
Write "path" in "Variable name field"
paste the directory of compiler in "Variable value field"
Click OK.
Click OK again...
DONE :)
Note: This is not the path of you program file, it is the path of java compiler. You can save your program any where in your computer and when you open command prompt in order to compile your program, you must be in that particular folder where your program exists...