Display Calibration on Windows

I'm pretty certain that I know how to calibrate a display on a Windows PC. I've done it many times. However, I have recently questioned my process because on a recent calibration I could not actually see a difference before and after calibration. I think I might be missing a step. Can someone point me to some document or article outlining how to calibrate a display on a Windows PC? Are there "gotchas" with respect to administrator privileges or anything else? We will be using basICColor as the calibration software. Thanks in advance for your help. Ken Fleisher