iPhone 4 problem: black screen and it doesn’t stop vibrating

I heard a funny sound just now and, as I approached my phone, I noticed that itโ€™s vibrating. I thought that Iโ€™m getting a call but when I hit the home button to switch on the screen, nothing happened. The screen stayed black and it kept on vibrating. I tried holding down the lock/power key … Continue reading iPhone 4 problem: black screen and it doesn’t stop vibrating