Hello Dave,
You should not have paid anything for trial software from Microsoft. The trial is time limited for a certain number of days. If you are a student you may be able to find an academic version of the software for much less than retail.
I don't know what you mean by the "poduct code" is blocked -- if you bought a book with the trial version, you would need to contact the publisher of the book to solve the problem with the blocked code.
You can download a trial version of Project 2010 from Microsoft if you haven't already. See:
http://technet.microsoft.com/en-us/evalcenter/ee404758
Julie
