You might see Office error 0x15
Step 1: Disk Clean-up
To delete files using Disk Cleanup
1. Open Disk Cleanup by clicking the Start button Picture of the Start button. In the search
box, type Disk Cleanup, and then, in the list of results, click Disk Cleanup.
2. In the Drives list, click the hard disk drive that you want to clean up, and then click OK.
3. In the Disk Cleanup dialog box, on the Disk Cleanup tab, select the check boxes for the
file types that you want to delete, and then click OK.
4. In the message that appears, click Delete files.
Step 2: system file checker
Run system file checker: sfc /scannow
1. Swipe in from the right edge of the screen, and then tap Search.
2. Enter command prompt in the search box.
3. In the list of results, swipe down on or right-click Command Prompt, and then tap or click Run
4. In the Administrator: Command Prompt window, type the following command and press Enter:
5. When the system scan is complete, try to install Office again.
How to Install Office:
1. Login to http://office.com/myaccount.
2. Enter the username and password.
3. Click on the Install button
Click on downloaded file and installation prepares.
Office installation will start after checking and preparing the configuration.
Follow the simple onscreen instructions.
Once installation is completed, click on All Done button.
Now, the Office Suite is installed and ready for use and the error is fixed
You may check if the Microsoft Office applications are working fine.
Note: If the issue is still not fixed, it can be a very critical problem with your computer. Windows registry and System files affected. It needs a manual removal and recommended to be performed by an expert.