certutil -hashfile C:\path\to\your\windows8.1.iso SHA1
Have you successfully installed from an original Windows 8.1 ISO recently? Share your experience and which hash you verified below (in the comments). Windows 8.1 Original Iso
Unlike Windows 10/11, which constantly churn background tasks, Windows 8.1 on an original ISO (with no feature updates) flies on old Core 2 Duo or Atom netbooks. It uses less RAM than Windows 7 and boots faster than Windows 10. Many retro-PC builders keep an 8.1 ISO specifically for old gaming laptops from 2010–2014. certutil -hashfile C:\path\to\your\windows8