The most reliable way to obtain a key is through the developer, CommView . However, since version 2.5 is quite old, they have transitioned to newer versions (like NEWT Professional 3.0). You may need to contact their sales department for legacy support.
: Capable of gathering over 200 items (hardware, software, product keys) from 100 machines in under 5 minutes. Hybrid Scanning newt professional 2.5 license key