Windows 10 has been out for a while now and it was offered as a free upgrade to Windows 7 and 8 users for the first year. Even after that Windows 7 is still by far the most widely used Windows operating system. Windows 7 is available in both 32-bit (x86) and 64-bit (x64) editions and has Home Basic, Home Premium, Professional, Ultimate and Enterprise versions. Only the Starter edition of Windows 7 does not have a 64-bit version. Both 32-bit and 64-bit editions of the 5 available consumer Windows 7 versions all easily fit on a single layer DVD.