1. Power off the Canvas
2. On the back of the Canvas, you will find a place were some ports are available (USB, HDMI...)
3. You'll find a small button next to these ports. Find something to push it like a pen or headset jack.
4. Push the button. Make sure you can feel that you are pushing it
5. While pushed, plug in the power supply
6. Wait 5 seconds and then release the button
If the reset is successful, you will see the logo comes up for 30-40 seconds. Let it finish and it will do auto reset. Once done, your Canvas should come back.