turning on my inspiron laptop

I am new to dell laptops, but not to computing but cant figure out what I am doing wrong... when I come to turn on the laptop by pressing the on button, the LED light flashes white once, but the computer doesnt appear to turn on (the screen stays black). After trying this several times the laptop will turn on but 'return to windows' and is locked.

Once turned on, the battery is charged 100% and I have the power adapter plugged in.

Is this because I am not giving the laptop enough of a chance to turn on before mistakingly switching it off again, or is this some kind of intermittent fault?