I'm running Windows98 on an Athlon T-Bird 800, with 128 PC100 RAM. I do experience some freezing when rendering or importing objects, and the occasional crash, I have never had a problem whilst using the parameter dials.

In your situation an uninstall/reinstall would be my first thought. If you uninstall via Control Panel, it should lave your library intact (all your figures, props textures, etc). It's a fairly easy procedure really.

If the reinstall did not help I would start looking at the configuration of my system, I use a permanent swap file of 512 MB virtual RAM. Apart from that, see if you can disable anything running in the background that may be conflicting or eating up resources, anti-virus is usually the only thing you absolutely need. Look at your graphics card setup, and run the Windows DirectX diagnostic tool DXDIAG.EXE.

It's Curious Labs software, so get on to them and hound them till it does work.