Why ask Google? Google didn't make it. Microsoft did. Microsoft knows and tells you in
http://office.microsoft.com/en-us/support/system-requirements-for-office-2013-and-office-365-proplus-HA102785958.aspx
Note: I found this by a searching (in Google indeed, although Bing would have been fine also) for OFFICE 2013 SYSTEM REQUIREMENTS. That last two words do the trick for nearly every program; it's very useful for games also.
Kees
Is the new Microsoft 2013 - Home and Student full version which I am about to order compatible with Windows 7 and Windows 8.1 Google search does not seem to contain any answers. Thank you.
christy.

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