Could not load file or Assembly `System.Windows.Forms , Version=4.0.0.0` cannot find the file

I am using reflection to search through assemblies that contain a certain interface, the one i am trying to find is a windows form that implements that interface, however the error i am getting claiming it cannot load the file, could it be down to not using reflection correctly or loading in the file properly.

string[] files = Directory.GetFiles(Environment.CurrentDirectory, "*.dll");

            foreach (string file in files)
            {
                try
                {
                    Assembly da = Assembly.LoadFrom(file);

                    foreach (Type type in da.GetTypes())
                    {
                        debugger = (IDebugger)Activator.CreateInstance(type.GetInterfaces().First(i => i.IsGenericType && i.GetGenericTypeDefinition() == typeof(IDebugger)));
                        break;
                    }
                    break;
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    continue;
                }
            }

            if (!(debugger == null))
                debugger.VirtualMachine = this;

Error

System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types.
Could not load file or assembly 'System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
   at System.Reflection.RuntimeModule.GetTypes(RuntimeModule module)
   at System.Reflection.RuntimeModule.GetTypes()
   at System.Reflection.Assembly.GetTypes()
   at SVM.SvmVirtualMachine..ctor() in C:\Users\Ollie\Desktop\Work\SimpleVM\SVM\VirtualMachine\VirtualMachine\SvmVirtualMachine.cs:line 49
System.IO.FileNotFoundException: Could not load file or assembly 'System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
File name: 'System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'