ReactOS is an open source operating system that is based off the same design principles, and aims to be a binary compatible replacement for Windows. ReactOS is currently in alpha.
Questions using this tag must relate to ReactOS. The OS is currently in alpha stage meaning it is not feature-complete and is recommended only for evaluation and testing purposes.
The minimum requirements to install ReactOS are:
RAM: at least 64 MB, recommended: 256 MB
Processor: x86 or x64 architecture, Pentium or later and compatibles;
HDD: IDE/SATA with minimum 350 MB of free space on the primary partition
(please note that some SATA controllers may not work with ReactOS)
FAT16/FAT32 primary boot partition
Video: VGA compatible video card (VESA BIOS version 2.0 or later)