When I open this TrinfinDVaultInstaller.exe package, registration window appears and when I use the key which is given then display message is "Key is fully used". Why?
That message actually means the key you have has reached its maximum activation limit. Typically, there is nothing to do in this case except contacting the developers of the application to issue a new key that you can use to register the product.
You can use the following contact information to get in touch with the developers: http://www.trifuturein.com/contactus.html