If you have created any custom style sheets on your old computer, export them first so that you can import them on the new computer.
When the new computer arrives:
If you purchased PerfectIt, you need to enter your license details to unlock the full version. To do that, run PerfectIt on any document and you will be prompted for details. License details must be entered exactly as sent. You should copy and paste the license details across (do not attempt to type them out).
If you don't have your license details, you can retrieve them here. Just enter the email address that you used to buy PerfectIt, and you'll get an email with your registration details.
If you have custom styles to import, click 'Manage Styles', then click the import button and bring the styles that you exported in one by one (making sure you give each one a new name).