Error Messages :
1. Delete the existing folder for Microsoft Office which is located on :
C:\Program Files\Microsoft Office.
C:\Program Files\Microsoft Office 15
2. Start - run - type regedit and press enter, find the below registry and delete it (please backup your registry before you change anything on it) :
HKEY_CURRENT_USER-Software-Microsoft-Office (delete "Office" Folder only)
HKEY_LOCAL_MACHINE-Software-Microsoft-Office (delete "Office" Folder only)
3. Restart the computer and try to run the installation again.