So, my sister was fooling around on my laptop, and somehow managed to change the color display. After that, system preferences became unresponsive, so I forced quit. After that, it would be unresponsive every time I opened it. My other apps like Safari and Chrome would shut down within a few seconds of opening them. So, I tried restarting. When I tried to turn it back on, it got stuck on the white startup screen with the apple logo in the center. It's still stuck that way! It's a school laptop, and winter break ends soon. I need this fixed ASAP, thanks!