Windows 7 Home Prem OA

I have a question, just recently I have gotten an HP Compaq 610, it came with windows 7 home prem preinstalled, every time I open up microsoft office it asks for the product key, I typed the on that was located at the bottom of my computer, it said it was the wrong, how do I get the correct product key for Windows 7 Home Prem OA?

Are you sure it isn't the 90-day Office Trial put on most p.c.'s as a MS promotion?

You would normally have to pay more to have Office installed if it isn't the trial version.