How can I set "Office 365 2013" as my 'default' for all "Office 365 2013" programs? I have "Office 2010 Home and Business" on the computer and wish to make use of both set of programs. I would appreciate an answer in due course. Thank You.

Hi,

According to your description, my understanding is that you want to make Office 365 as the default program for opening Office files instead of Office 2010. Am I right? If yes, you can also follow the steps to change the open option.
1. Right-click a document, click Properties.
2. On the document properties page, besides Opens with, click Change.
3. On the Open with page, select the Word 2013.
4. Click OK.

Reference:
Change which programs Windows uses by default
http://windows.microsoft.com/en-in/windows7/change-which-programs-windows-uses-by-default

If I misunderstand something, please feel free let me know.

Regards,

George Zhao
TechNet Community Support