(Official)

Before downloading and installing the software, ensure your computer meets the minimum hardware and software prerequisites to handle intensive 3D rendering. Minimum Requirement Recommended Requirement Windows 7 / 8 (64-bit) Windows 10 (64-bit) Processor Intel Core i5 or equivalent Intel Core i7 or Xeon (Quad-Core) RAM 16 GB or higher Graphics Card Dedicated GPU with 1GB VRAM NVIDIA GeForce GTX / Quadro (2GB+ VRAM) Storage 5 GB free HDD space 10 GB free SSD space Prerequisites .NET Framework 4.5+, Visual C++ .NET Framework 4.5+, Visual C++ Detailed Instruction: How to Install Optitex 15

That being said, there are some possible ways to obtain Optitex 15 for free or at a reduced cost:

Possibly, but driver conflicts are common. You may need to run in Windows 7 compatibility mode. Optitex no longer supports v15 on modern OS.