Reinstall Office on a PC through Microsoft HUP:
Go to microsofthup.com.
Select the Order History link in the upper right-hand corner of the page.
Enter the work email address that you used to buy Office. This will send an email to yourself that contains a link to your order history.
In the email you receive, select the link to view your order history.
On the Order History web page, select your order number.
On the Order Details web page, select the Install button for Office, Visio, or Project.
After you install Office, you’ll need to enter your product key.
Get your Microsoft HUP product key, if you don’t have it.
In the Sign in to set up Office window that appears when you first start an Office app, select I don’t want to sign in or create an account.
In the Enter your product key screen, enter the product key to activate Office.
Agree to the License terms by selecting Accept and start Word.
for more details, visit : www.office.com/setup