Whenever I load the Minecraft Launcher It gives a Grey Screen

Ever since i started playing minecraft  i have been experiencing a bug where, whenever i loaded the launcher up, it would give a grey screen but i could still click on buttons. I worked around this by looking at an image of the login screen and moving my mouse to try and find the text boxes. I finally got fed up and now need to know how to fix this. I have tried restarting my computer and have deleted all minecraft files except for the saves. Please tell me how to fix this.