If the Minecraft launcher won't start or you receive an error message saying, ‘Pixel format not accelerated’, you may have outdated video card drivers.
The error message ‘Pixel format not accelerated’, also referred to as a problematic frame, is usually caused by having out-of-date or bad video card drivers. For more information, see Update Video Card Drivers.
While most of the time this error is caused by the video card drivers being out of date, it can also be caused by a gamepad device, or something being interpreted as a gamepad device (headphones, controller, etc). If this is possible, try disconnecting any other devices that you have connected to your computer, then restart Minecraft.