Hi,
the lates stable version for v3.x series was 3.08.4:
viewtopic.php?f=85&t=68978
Unfortunately Nvidia has broken the drivers some time ago under Windows, and versions prior to 4.02.1 are no longer working with recent Nvidia driver versions.
Better to install c4doctane v4.05-R7, fully compatible with latest Nvidia driver.
You can find 4-05-R7 by visiting your personal Downloads area:
https://render.otoy.com/account/download_archive.php
ciao,
Beppe