I tried to render something on blender and it just didn't work. It started rendering like usual but at the end of the render it didn't give me any files... It was suppose to give me a .png in "desktop" but instead it just rendered and didn't give me the render!
Have you actually saved it ?
Blender does the render and displays it but doesn't automatically save it as an image.
To save it, use the top left of your Image Viewer window click on "Image" > "Save As" and give your file a name and save it.
in 2.79 use the UV/Image editor window
If you want to save the render automatically you need to render as animation (CtrlF12), just set the range to render only one frame.
Do a little more research and/or show that you have done some research next time you want to ask something here. Some folks on this forum don't have quite as much patience as I do and might reject your question for showing too little (if any) previous research