I read through some tutorials on BitBlt and copied the code. It was part of the lander tutorial in which the author demonstrates how you can copy an image, and how you can invert it. I copied the code into a project, and it worked fine. I modified it a little, and it won't work. I am fairly experienced with API functions. BitBlt is the only one I have trouble with. Any tips? Tutorials simplifying the use? Thanks.