Look here:
MSDN: AppDomain.Load Method[
^]
It does not take assembly path as a parameter. The way you define, it is trying to find an assembly that has name 'C:\temp\good.dll'. This is wrong.
Try:
string fileToLoad = @"C:\temp\good.dll";
AssemblyName assamblyName = AssemblyName.GetAssemblyName(fileToLoad);
AppDomain myDomain = AppDomain.CreateDomain("MyDomain");
Assembly myAssambly = myDomain.Load(assamblyName);