I was having some kind of hardware issue. The Keyspan passed all testing. What was happening is that when I would go to calibrate, the machine would lock-up (very scary thing to have happen repeatedly) and I would have to hard-reboot. So, what I did was standard problem-solving. First, I disabled all non-essential programs; anti-virus, anti-Malware, an app called 'DeskPins', Adobe monitor, etc. I shut down all non-essential apps and services. Then, I unplugged all non-essential USB devices. Printer, USB audio device, etc. Then, I tried calibration again and it worked. I also tried it outside of Windows Serial Mode, though I don't know if that was the issue. It could be that my Malware or Anti-Virus program was interfering too, but I seem to recall having those when I first calibrated, since I always run that software. Weird problem, but the cutter cuts nicely now. FINALLY. Sheesh.