Follow these steps to resolve this issue:

  1. Archive the previous QuarkXPress Installation and move it to different location on your machine.

  2. Download the QuarkXPress 7.5 Full Installer from the Quark Website at the following location:

  3. Un-stuff the installer in a new folder.

  4. Run the QuarkXPress 7.5 Installer; it will prompt you to either install Evaluation Version or Full Version.

  5. Select Full Version, type in your Validation Code, and complete the Installation process.