Because this is legacy software, it runs incredibly fast on modern hardware. 2.0 GHz or higher. RAM: Minimum 1GB (4GB recommended for Windows 10). Storage: 4GB of free hard drive space. Interface: USB or Serial port (for cutter connection).
I can provide specific troubleshooting steps for your hardware!
Mastering FlexiSIGN-PRO 8.1v1: The Ultimate Guide for Windows XP to Windows 10
: FlexiSIGN-PRO 8.1v1 is commercial software. SAi no longer sells new licenses for version 8.x, but if you have a valid license key (dongle or serial number), you may download the installer from authorized archives.