ArcObjects tool development - Could not find some namespaces

I worked on multiple ArcObjects Desktop applications several years ago. In those project, I needed to add some references, e.g. ESRI.ArcGIS.ADF, ESRI.ArcGIS.Utility (this one is in ESRI.ArcGIS.ADF?), etc., which could not found in my CPU. Where could I find their dlls?
Besides, in the created project, I could not add ESRI.ArcGIS.Geoprocessor.dll and ESRI.ArcGIS.GeoprocessingLib.dll. The error message shows that the xxx.dll can't be added. Please make sure that the file is accessible, and that it is a valid assembly or COM component.
Please help if you can. Thanks.