Since this version is no longer actively marketed by SAP, finding a "free download" link can be tricky. However, there are official ways to obtain the necessary files:
You are moving an old app to a 64-bit environment (like Windows 10 or 11) where the older 32-bit runtimes might be missing or misconfigured. How to Get Crystal Reports 10.5.3700.0 Legally Crystal Reports 10.5.3700.0 Free Download
Powering WinForms and WebForms applications built on .NET Framework 2.0 or 3.5. Why Do You Need This Specific Download? Since this version is no longer actively marketed