I had the same problem Russell, I searched a few sites until I eventually hooked up with the 6 model. That in fact may be the Student model on the other sites, but I investigated that also and It seems to be the same program. Let me say this is a very versatile and thorough program. I have been playing with it now for 2 weeks and have not even scratched the surface of what it can do. I do know that there is a pay program that is even more complete but that only offers more of the differing types of op-amps and transistors and more esoteric tubes but the capabilities to construct and model circuits is the same. I would post the site but I am not sure if that is allowed.