JAR File not exececuting which is build by netbeans

JAR File not exececuting which is build by netbeans

I am a Beginner in Java GUI and am using Netbeans 7.3 to use Swing
Components, the problem is that all was working fine, but one day when I
Clicked Clean & Build and tested the JAR file, it was not executing, I ran
it in the Netbeans and It is working fine.
Then I thought that it would be a problem of Build Properties so I
compared build properties from a project which was working fine with Jar
file but I cannot find any difference, The problem is that when I
double-click the JAR file, no Error is shown, I tried many ways like
executing it from cmd but It did'nt worked.
Can anyone help me out What could be missing, and one thing more that is I
even tried to build my project on another computer through Netbeans but no
use.