Microsoft Windows Thin: Pc X86-iso

However, the ISO is considered by the community. Here are legitimate (historical/archival) sources:

While a 64-bit version exists, the is the holy grail for legacy hardware because: Microsoft Windows Thin PC x86-iSO

The "x86" designation is critical. The 32-bit version retains full compatibility with 16-bit subsystems (rare in modern OSes) and supports older CPU instructions. However, the ISO is considered by the community

Runs on 32-bit UEFI and legacy BIOS systems. Does not support 64-bit-only CPUs. Microsoft Windows Thin PC x86-iSO

Are you trying to install this on a specific piece of hardware, or do you need help finding a modern lightweight alternative?