Compression technology (ZIP, RAR, 7z) can shrink files, but only by so much. The maximum realistic compression for a Windows ISO is about 30-40% — taking 3 GB down to maybe 1.8 GB. without deleting nearly everything that makes it Windows.

. Any file claiming to compress this entire operating system down to 100 MB is likely fraudulent and poses severe security risks. Why "100MB" ISOs Are Dangerous

Remember: