Shutdowns

Hi! I’ve had unexpected shutdowns with my MacBook Air recently, I did the reset of my SMC but it still shutdowns... Also, when I close the screen and openit back, the computer is completely closed (instead of just opening it back). I also have this message (see picture) that shows up even though I don’t have anything plugged in my USB space.

What is happening? My computer is going crazy... Help! Thank you!