i have set the JAVA_HOME properly and when i type in set in the command prompt, it print out all the variables and JAVA_HOME was included.
However, when i type "(JAVA_HOME)\java-version" in the command prompt, i got the response: "\java-version was unexpected at this time".
Then, the error has not change, it's still giving me: "JAVA_HOME point to an invalid java installation(no java.exe found in C:\program files\java\jdk1.8.0_51\bin)". Hence, i can't still install it.