If your computer is made by Apple, please select the "Apple Mac" option.

If your computer is any other brand (Dell, HP, IBM, SONY, ASSUS, ACER, TOSHIBA etc) it's most likely running a version of the Microsoft Windows operating system. If you are unsure whether your computer is using the Windows 7 operating system or a Windows 8 operating please visit this web page.

On that web page, underneath the title, it will tell you which version of Windows you are using.

Example: