It modifies and suppresses the specific system files and core registry keys responsible for validating the operating system's license.
Traditional loaders often broke when Microsoft released major Service Packs or specific security updates (like KB971033, which specifically targeted activation exploits). Chew-WGA's aggressive patching method was often more resilient to these updates.
Once applied, the tool typically prevented the "This copy of Windows is not genuine" notification from reappearing. Simplistic UI: