If you are using any kind of extension cord between the Pegasus board and the sensor, make sure it is the right kind of extension cord. They come in both "straight through" and "cross over" style.
I had the wrong kind.
Changed that and problem solved.

I have the same problem. Windows 10. If I start the computer with no sensor plugged in, it comes up fine. If I plug in the sensor and start up the computer it will not come up. So I cannot set it up to function automatically which makes this unit not worth the added money I spent on it. It does work...

There are manual power sliders for both A & B dew heaters.
To the right of the sliders is a box that you can put numbers in.
To the right of that box is a black box.

What do those boxes do?

Thanks
Greg