Setting path and classpath for java in windows XP, Vista and Windows 7

• Click the Start button in the lower left of the screen.
• Select Control Panel from the pop-up menu.
• Choose System from the submenu.(Click Advanced system settings on left in Vista and Windows 7)
• Click the Advanced tab.
• Click the Environment Variables button near the bottom and you will see two lists of variables.
• Look in the System variables list for a variable named CLASSPATH. If you find it, click Edit. If you don't find it, click New and enter CLASSPATH in the Variable name field.
• The Variable value field is a list of file paths of directories or jar files. The first thing in this list should be the current directory, which is represented in windows just as it is in Unix, as a single period. If there's more than one thing in this list, separate items with a semicolon. For example, my CLASSPATH variable starts with these three items (there are a couple more, but this should be enough to give you the idea). The only part you need is the first "dot".

  .;C:\classpath\com.fredswartz.ezgui.jar;c:\classpath\TableLayout.jar;

  I put extra libraries that I want to be searched in a directory named classpath, but you can choose any name. 
• Now just add the following depending on your environment installed on computer. eg.:
  D:\Program Files\Java\jdk1.6.0_24\bin

Similar way go for path as well.