The firm announced last month that the operating system was finished, and the release to manufacturing version is being made available for early adopters and technical subscribers.
The public beta of Windows 7 will be limited to English language versions at launch, but other languages are expected to be added in October through the TechNet and MSDN pages. The operating system is on track to be released to the general public on 22 October.
Pirated copies of Windows 7 appeared briefly on file-share sites last week until Microsoft deactivated the leaked activation key, which was widely thought to have come from Lenovo. Microsoft warned potential downloaders to wait for the official release.
The final version of Windows 7 will cost £149.99, £219.99 and £229.99 for the Home Premium, Professional and Ultimate versions respectively. Upgrades from existing installations will cost between £79.99 and £199.99.
Both hardware and software versions of the operating systems are expected to be released today.
New light-guiding nanoscale device can control and monitor a nanoparticle trapped in a laser beam with high sensitivity
Optical traps are scientific instruments in which a focused laser beam is used to exert an attractive or repulsive force on a microscopic object to hold it in place
Scientists estimate that the exoplanet has already lost up to 35 per cent of its mass over its lifetime
The observations were made using the Atacama Array in the Chilean desert
J1043+2408 was observed for more than 10 years, and its radio light curve exhibited a periodic signal repeating in about 563 days