The protection key is actually a dongle that needs to be inserted into one of the USB or Serial ports on the back of the computer. The protection key ensures you have an original copy of the software licensed to your name. Unfortunately, it's impossible to obtain this key because the website of the developer is not working or it has been discontinued. To get in touch with them, start the application and go to Help > About. Most likely there will be phone number or email addresses you can use to get in touch with them.
