If you can't install Office because the Install button isn't working, it might be because of the following.
The install button is greyed out
If the Install button is grayed out, your Office 365 subscription might have expired. Select your subscription from the list below to see the steps for how to renew it.
Nothing appears to happen when I select the Install button
If nothing appears to happen when you select the Install button, try one of the following options.
Option 1 - Select Run to start the install
You might need to choose the Run button (or the equivalent button depending on the browser you're using) at the bottom of your screen to start the install.See Download and install or reinstall Office 365 or Office 2016 on a PC or Mac for step-by-step help.
Option 2 - Use InPrivate browsing
Try the private browsing option for your browser.
Right-click the browser from the task bar and select New InPrivate window (or depending on your browser, New incognito window or New private window).
In the new window, go to office.com, sign in with your Microsoft account or work or school account.
Select Install, and then Install again.
Option 3 - Start Internet Explorer without add-ons
Find the version of Windows you're running in the table below, and follow those steps to open the Run command.
In this version of Windows
Do this to open the Run command
In Windows 10
Right-click the Start button (lower-left corner), and choose Run.
In Windows 8
On the Start screen type Run, and then choose Run in the list of results.
In Windows 7
Select Start > Run.
Type iexplore-extoff and choose OK.
To reinstall Office select the version you want to install and follow those steps.
Option 4 - Delete your temporary internet files
When you delete your temporary internet files, your links and favorites won’t be deleted. However, the list of websites you’ve visited, cookies, information entered into web forms, passwords, and other temporarily saved information will be deleted.
In Internet Explorer, type Alt + X, and then choose Internet Options.
On the General tab, under Browsing history, choose Delete.
Select the check box next to each category you want to delete, and then choose Delete. This can take a while if you have a lot of files.
After the files have been deleted, sign in to install Office.
Option 5 - Reset Internet Explorer settings
Important: When you reset Internet Explorer settings, your links and Favorites will be deleted and Internet Explorer will return to the state it was in when you first installed it. Resetting Internet Explorer isn’t reversible.