| DirectX SDK | 
The DirectDrawSurface7.SetLockedPixel method sets a single pixel to the specified color and updates the locked surface.
object.SetLockedPixel( _ 
    x As Long, _ 
    y As Long, _ 
    col As Long)
If the method fails, it raises an error, and Err.Number is set.
You must first lock the surface with a call to DirectDrawSurface7.Lock.