I'm not exactly a Tech type of person but sometimes the newer generations have more glitches. If what doesn't work is your home button thing then it's because there is a sticker behind that button and when that button isn't sticky anymore then you can't press it. Either go to a professional person to get it fixed or look on YouTube which I think there may be some videos. You didn't mention that if it was the home button or if it was the power button. Sorryy This may not be what you want ..

And by white you mean...? What were you doing before? Whatever try hard resetting it :P hold the sleep and home button together for 10 seconds so it completely shuts off, then turn it on.

Try connecting to iTunes and perform a restore... Make sure you back it up first. All your music and apps will be gone... but it should work again. or your screen is messed up.

DFU first, then restore