If you have Win2K+, try using alpha blending. Make a circle in Paint/Photoshop etc. Make sure it sits on a solid colour background, like white (255,255,255), green (0,255,0) etc. Use it as the background for your window. Then set your window as Layered (SetWindowLong and WS_EX_LAYERED) and use SetLayeredWindowAttributes to make the form transparent. Pass the long rgb value of your background colour, and voila, Windows draws that colour transparent.