The iPhone is a smartphone that allows users to make and receive calls and text messages, check their email, download applications and browse the Internet. Many users are so dependent on their iPhones that they are highly inconvenienced if the screen suddenly stops working. Different reasons could be behind the malfunction, but you might be able to get your iPhone working again without professional help.
If your iPhone screen is blank and will not come on, the battery may have died. Try turning the phone on by holding down the power button on top of the phone. If nothing happens or if you see a red battery symbol on the screen, you need to plug the phone into a power adapter or computer using the supplied USB cable to charge it. Once you plug the phone in, it sounds a tone to indicate it is charging, and the screen displays a battery with a lightning symbol.
Your iPhone screen might also fail to come on if you have applications on your phone that have frozen; force quit these. If you have cracked your iPhone screen, this could affect its function, but this requires professional attention. Setting your iPhone's brightness setting to a low level can make it seem as though the screen isn't coming on as it is difficult to see the display; this situation calls for a reset of your iPhone.
Reset your iPhone by holding down the power button on the top of the phone and the home button underneath the screen together for at least 10 seconds. To force quit a frozen app, hold the power button on top of the phone until the red slider appears, then hold down the home button underneath the screen. If this doesn't work, reset your phone.
Purchase a protective case for your iPhone to prevent cracks or damage to the screen. To prevent the contrast settings causing the issue, don't set the brightness levels too low and don't allow other people access to your phone; they might choose the lowest contrast settings as a practical joke. To prevent your phone running out of a battery charge, charge it overnight so you can be sure it will last throughout the next day. If you are unable to fix your screen problems at home, take your phone to a professional for advice.