Hi, thank you.
It's the Windows 8 computer.
But, even under Windows 8, Office 2013 Preview has been working before!
It's only after I reinstalled Windows 8, and reinstalled other programs too, that I can't install Office 2013.
The exact error message: "Couldn't install. We're sorry, but we had a problem installing your Office program(s). Is your internet connection working? Do you have enough free space on your main hard drive? Please try installing again after you've checked the above."
I also have checked the Control Panel. In Programs & Features Office 2013 Premium is not present (Office 2010 is).
As I mentioned before, Windows 8 and Office 2013 Premium both have been working on this computer before I reinstalled my main programs.
Office 2013 (English, 32-bit) (624 MB)
Office 2013 (English, 64-bit) (702 MB)