One thing in the past I have done with keygens is run them on an old computer in a sandbox then copy the serials and activations over. The problem is when you need to replace things like exe files and stuff as these need to be run on the computer where you are installing to. Some may be fine but its always felt a bit like playing Russian Roulette when I have done it in the past.
Actually the worst virus I ever got years ago now was in an old DAZ exe installer someone had tampered with. I had to reinstall my entire PC as it locked it up and deleted loads of stuff. Glad I dont have to use them now.