Android studio Install issue for Win7(Can't start the program)

When you  installed the android studio,
In Windows 7 as me , I can't start the program.
so here is how solve it.
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• Open Start menu > computer > System Properties > Advanced System Properties
• In the Advanced tab > Environment Variables, add new system variable JAVA_HOME that points to your JDK folder, for exampleC:\Program Files\Java\jdk1.7.0_21

And now it's work!