ReactOS is a free and open-source operating system with Windows compatibility up to NT 4. See more at

Windows 10

These are the latest unmodified Windows 10 ISOs mirrored from Microsoft. If you already have Windows 10 installed, you can use Windows 10 Update Assistant to update to the latest version.

You can buy cheap activation keys here.

Spring 2020 update (20H1/2004)

November 2019 update (19H2/1909)

May 2019 update (19H1/1903)

October 2018 update (Redstone 5)

April 2018 update (Redstone 4)

Fall Creators update (Redstone 3)

Creators update (Redstone 2)

Anniversary update (Redstone 1)

Windows 7

These are the last Windows 7 ISOs released. You can install updates released after these ISOs with Windows 7 SP1 Convenience Rollup.