Dell Latitude E5500

Just bought a new Dell laptop for my daughter for christmas. She has had it three days...now, when we try to turn it on, it blinks like its coming on, then a lil lock with the letter A in it starts blinking, and thats all it does. Has she hit a button or something, maybe locked something?? I dont know, and the laptop did not come with something that shows what all the lights are for. Please help me, shes driving me crazy!! Thanks!!