The OrCAD 10.5 license file is a typical of mid-2000s EDA software. It is reliable only on legacy Windows XP systems with matching hardware. For any serious modern PCB design, you should upgrade to a current OrCAD release (or an open-source alternative like KiCad), as the 10.5 license mechanism is obsolete, unsupported, and increasingly difficult to maintain on today’s operating systems.
Once you've obtained your license, you'll typically receive a license file (often with a .lic extension) that you need to install on your system. Here are the general steps: Orcad 10.5 License File