How to install Office 365 ProPlus
If I have an older version of Microsoft Office on my computer, can I still install Office 365 ProPlus?
No. All other versions of Office must be removed before installing Office 365 Pro Plus. Remember that you will need your product key should you wish to reinstall your previous/older versions at a later stage.
Should I install 32-bit or 64-bit version?
The 64-bit version is installed by default unless Office detects you already have a 32-bit version of Office (or a stand-alone Office app such as Project or Visio) installed. In this case, the 32-bit version of Office will be installed instead.