I have down loaded the 30 day trial version and have been checking out the features. A retail version has been purchased for me for Xmas.
My question is will the product key that comes with the retail version work on the downloaded trial version. Or should I uninstall the down loaded version and start a fresh.
No need to uninstall. You convert the trial to retail with the product key you receive. To remove the watermark from projects you created during your testing you can remove it by following this entry from the FAQ: How can I remove the watermark from projects created with the trial version of the program?
Insanity is hereditary, you get it from your children
Welcome to the forum.
As Neale says, you just need to plug-in your S/N and edit away.
Being new to PrE, this LIST of some of the resources for learning might be useful.
Merry Christmas, and happy editing,