Cube Flying Upwards when it should fall down!,Cube flying upwards when gravity should be happening! Help!

So when I start my game, my cube flies up instead of falling like gravity. I have gravity in place and all of my input as well. I think I have made just a tiny mistake but I need a keen eye to spot it. Thank you for helping -A Confused Coder

,So every time I press go my cube flies upwards. I have a gravity and floor and all code should be in order. I'm guessing something small happened and I just need a keen eye to help out. Thank you, the code is attached in the question. -A Confused Coder