I cannot play rollercoaster, I keep getting a message - access denied -violation
^^You're going to have to be more specific with the name if you expect anyone's help. There is no game that is just called "rollercoaster" to my knowledge.
The problem is that your registry has too many incidents of the program and they interfere with each other. You must completely uninstall the program, clear all incidents of the program from your regtistry and then reinstall the program. I recently went through the same problem and now everything works fine. For more specific help, you can write to me via email. The problem could have been generated by updates or reinstallation of the program. The registry rarely deletes all the files associated with any program and you need to do this manually. Good luck