To summarize, I encourage you to explore legitimate options for obtaining a Guitar Pro 6 license key. If you're looking for a free solution, consider using the free trial, open-source alternatives, or Guitar Pro 7's free version.
If you're a student, ask your music department if they have educational licenses (many do). If you're a teacher, consider buying a single license and using it on multiple classroom computers (check Arobas Music's terms). If you're just broke, TuxGuitar runs on that old laptop you didn't throw away. guitar pro 6 license key free