The promise of a "10MB Windows 7" is technically impossible and is a classic lure used by malicious websites. The website fullversionforever.net falls into the category of "Warez" or software piracy sites that profit from distributing compromised software. Interacting with these downloads puts your personal data and hardware integrity at immediate risk.
A legitimate Windows 7 installation is over 2–4 GB, so a 100 MB file cannot contain a functional OS. These downloads often carry viruses, ransomware, or unwanted software. Microsoft no longer supports Windows 7 (since January 2020), making it insecure even if obtained legitimately. The promise of a "10MB Windows 7" is