motor won't start

Hey guys. So I have the phantom 3 and I just put the protection crash blades on it and now the one motor won't start up. It started up perfectly fine before I put them protection blades on.. What can be the problem?

I bought a new never been openedPhantom off of eBay (verified and excellent feedback on the seller). The LED light on the remote control is solid green. Is that normal? I am able to calibrate the compass fine, but when I bring the sticks together on the controller it gives me quick flashes of...