Code:
#define STRICT
#include <windows.h>

LRESULT CALLBACK WndProc(HWND hWnd, UINT iMsg,
									WPARAM wParam, LPARAM lParam)
{ switch (iMsg)
  { case WM_LBUTTONDOWN:
      MessageBox(hWnd, "Left-mousebutton pressed", "Info", MB_OK);
      return 0;
	 case WM_RBUTTONDOWN:
      MessageBox(hWnd, "Right-mousebutton pressed", "Info", MB_OK);
		return 0;
    case WM_DESTROY:
      PostQuitMessage(0);
		return 0;
  }
  return DefWindowProc(hWnd, iMsg, wParam, lParam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
                   PSTR szCmdLine, int iCmdShow)
{
  const char *const szAppName = "tradwin";
  WNDCLASSEX wndclass;
  HWND hWnd;
  MSG msg;

  wndclass.cbSize = sizeof(wndclass);
  wndclass.style = CS_HREDRAW | CS_VREDRAW;
  wndclass.lpfnWndProc = WndProc;
  wndclass.cbClsExtra = 0;
  wndclass.cbWndExtra = 0;
  wndclass.hInstance = hInstance;
  wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
  wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
  wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
  wndclass.lpszMenuName = NULL;
  wndclass.lpszClassName = szAppName;
  wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
 
  RegisterClassEx(&wndclass);

  hWnd = CreateWindow(szAppName, "Tradwin: Press a mousekey.", 
                      WS_OVERLAPPEDWINDOW, 0, 0, 640, 480, 
							 NULL, NULL, hInstance, NULL);
							  
  ShowWindow(hWnd, iCmdShow);
  UpdateWindow(hWnd);
	
  while (GetMessage(&msg, NULL,0,0))
  { TranslateMessage(&msg);
    DispatchMessage(&msg);
  }
  return msg.wParam;
}
I get 5 errors....