Follow these steps in order:

1) Download and this ROM program.  
2) After you click on the website, http://wabbit.codeplex.com, download it onto your computer. Remember where you saved these two files.
3) After download, open the .exe file.  
4) When prompted, load up the saved ROM program.
4) Click on the "Debug" file to turn on the calculator.
5) Click on "View" and "Enable skin."