Unable to launch the application (topcoder arena) [solved]

sometimes after clicking "ContestAppletProd.jnlp" almost everyone (who use topcoder arena) have faced this kind of problem. didn't we?
here is the screenshot i am talking about. 

What can we do to resolve this problem? 

- All we have to do is Clearing Java Cache.

lets see how can we clear Java Cache in 3 simple steps (with picture).

Step1: Goto "C:\Program Files\Java\jre7\bin" and run "javacpl.exe". 

we can do it in another easier way. press start button, write "java" and then you will see "configure Java" appears. just click on it. 

Step2: Click "View" (General Tab -> Temporary Internet Files -> View) as shown in the picture. 

Step3: You will find "Competition Arena" here, select and remove it. 

That's it. you are done.

Now re-run the "ContestAppletProd.jnlp". You won't see the problem again. :)

How to reset the trial period of any software

Uninstall the software and follow the steps.

Step1: After uninstalling software, Open RUN(Windows key + R) and type regedit and hit Enter.

Step2: Now Registry Editor Window will appear and here navigate to HKEY_LOCAL_MACHINE \ SOFTWARE \ Your Software name from left pane of this window. If you find any Key name with your software name then just Delete that Key.

Step3: Similarly navigate to HKEY_CURRENT_USER \ Software \ Your Software name and if you find any key with your software name then just Delete it and close the Registry Editor window.

Step4: Again go to RUN and type %temp% and hit Enter.

Step5: Now Delete all the things in that folder. Don’t worry these are the temporary files and not necessary for your operating system.

Step6 Now go to C:\Users\your username here\AppData.Under AppData open all three folders"Local", "Local Low" and "Roaming”and check. Under these three folders if you find any folder or anything with your Software's name, just delete it.

Step7: Now Restart your PC and install the expired software and you can use it again for trial period.