The first line in the "System" window tells you what version you are using. My guess is it is the OEM Home edition.
I understand you have found the cd key in your Windows 8 installation?
Otherwise, download and install "Speccy" (Free) which will give you that info and full details of your computer. Far more info than in the built in system tools program
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If you disable the uefi in your bios, and then make a full image of your existing installation, using Macrium or a similar program, and include the MBR. You could then install a linux distribution in a second partition of its own and, after that recover the image to its origianl partition.. If you then use Easybcd, you can add the path to the linux OS as a dual boot.