My Dell Downloads does not have MS Office available for download. That has to be reinstalled using an installation disk. or using your activation key that came on a card with the new computer. What version of office did you purchase with the computer? Here are MS instructions:
office.microsoft.com/.../download-backup-restore-microsoft-office-products-FX103427465.aspx
Note that your computer might have had Office Starter that used to be included for free. That cannot be downloaded from My Dell Downloads either.