What other ways can I save documents to the computer?

I'm really annoyed with this Microsoft Office 2010. They want the product key code, in which I do not EVER remember seeing it when we purchased this new computer from Best Buy.

I kept all documents, and there is nothing.

Best Buy will not help.

So, now I am stuck like many others, that cannot access important documents. There is an orange icon now and telling me that either I put the code in or now I have to pay an outrageous price to use the program to access my files.

Is there ANY way to access my files, without using Microsoft Office?

Before buying this newer computer, I had a computer for 8yrs and not once did I ever had to "pay" again to access my files.

Thank you all in advance for any advice you can provide me!