: This is a specific build of Windows 7. Builds are essentially versions of the operating system that are released internally or to a limited audience for testing purposes. Each build may include new features, updates, or bug fixes.
Understanding Windows 7 Builds: The Myth of Build 617600 and Safe OS Installation
: This denotes the 64-bit architecture, which allows the operating system to utilize more than 4 GB of RAM.
When people refer to a "full version" of an operating system, they usually mean a version that is complete and not an upgrade or a trial. The full version of Windows 7 SP0 x64 Build 617600 would include all the features and components of the original Windows 7 release, without any updates or service packs applied.
Often, authentic, unmodified ISOs (hashes verified) are hosted on platforms like Archive.org.