Try this:

Open the File using the password.

Then, click on the Microsoft Office button and click "Save As".

When the "Save As" dialog box appears, click on the "Tools" button which is
on the lower left of the dialog box.

Click "General Options".

Delete the password and click on "OK".

Finally, click on "Save" (make sure you have the desired drive and folder).

The file should now be saved without a password.

I hope this helps.

Good Luck.