Sculptris does not work properly on my computer

[FONT=Verdana, Arial, Helvetica]I watched a friend using Sculptris and was pleasantly surprised. But on my computer, Sculptris barely works at all. I have no idea why.

I am running Windows 10 with 8 GB of RAM (and only 50% used). I have a Wacom tablet (which often is at the root of UI problems). I installed the latest Wacom driver package. I also have a Logitech wireless mouse which I use in emergencies (like now).

When I load a sphere, some of the brushes work (crease, inflate, pinch, grab) but others (flatten, smooth) do nothing at all, even when the surface is very rough. My friend uses Sculptris routinely to do smoothing, but I cannot get it to work at all here.

Not sure how to proceed.

Smoothing works fine with MeshMixer BUT ONLY WITH THE MOUSE, not with the Wacom tablet.

I can barely read this message on my computer, because it is a black font on a dark gray background. How do I fix this problem?