My Acer Computer Is Looping At Startup Screen, Please Help!?

My friend owns a Acer 5517, had it less than a year, and once and a while when she turns it on it wont go to the log in screen to enter your pword and just loops through the "Acer empowering people" screen and windows is starting, but it just keeps looping. Please help, she tries to go to the F2 menu and F12 menu and she did something to fix it before but she can't figure it out now. Please help and thanks in advance.