Instead of chasing a fake 2040 key, use (lifetime license for basic antivirus) or purchase a legitimate 1–3 year key from a reputable reseller (often $15–$25/year). For a truly long-term solution, consider switching to a lifetime-license antivirus (rare) or using Windows Defender (free, built-in, and excellent when combined with common sense).
A: Without internet, AVG cannot download virus definitions. You are unprotected against new viruses. A local “valid” key is worthless.
The “keygen.exe” or “patch.exe” you download almost always contains: