Check "Run this program in compatibility mode for" and select or Windows XP (Service Pack 3) .
For 64-bit Windows 10 users (95% of modern PCs), the most stable method is running a virtual Windows XP environment. This is the #1 recommendation for "how to install jewelcad 51 in windows 10 top" . how to install jewelcad 51 in windows 10 top
Since Windows 10 usually disables legacy parallel or USB HASP keys, we use a software emulator to trick JewelCAD into thinking the hardware key is present. Check "Run this program in compatibility mode for"