Microsoft Word "Locked out"

I’m using MS Office 2007 since past two and is working great. Last night I saved all my documents normally as I do regularly. Today morning when I started PC and opened Word documents, I received the following message:

"This modification is not allowed because the selection is locked".

My own document wont allow me to edit or type anything though I dint made any changes. I retried entering my Product key but it is not even accepting the same. Can anyone please tell me what is going on with my Office and how can I fix it?

Did you purchased this Office Edition two months ago? Because such problems may also occur if you were using TRAIL version and it got expired after two months. Or it can also occur if you have not activated your office yet. Just to confirm can you just go to Word Options, click Resources and click Activate. What message do you see here?

Thanks for your reply friend. I got this laptop gifted by my relatives and i thought it was the genuine software. I was not aware if i'm using Trail. Anyways, now when i try to activate it by going into Word Options, it is not accepting the Activation codes i have.

What now?

I know that mine is not a trial and it was preinstalled. Do you know anything about ".docx" ?

So how can i gain acess to editing my documents or powerpoint

Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File
Formatshttp://www.microsoft.com/downloads/d...displaylang=en

I've tried this and it never works. I still can't access word