Cell phones have become a vital part of the daily lives of many people. As the technological capabilities of the phones have grown and their uses have diversified, they have become more relied on by the people who use them. When the phone stops working, it can be a significant source of stress on both a work and personal front. If the phone suddenly won't turn on, there are a few things you can try to get it going again.
Hold the power button down for five seconds or more. This can reset the phone on many models and possibly cause a reboot if the phone has frozen. If that doesn't work, take the battery out of the phone and wait at least 30 seconds. With the power source gone for an extended period of time, any glitches preventing the phone from turning on should be removed. After 30 to 60 seconds, replace the battery and see if the phone turns on.
The Power Source
The simplest explanation is that the battery is dead. Grab either a wall or car charger and plug the phone into a power source. Wait at least two minutes before trying to turn it on because if the battery is completely dead, it will need a moment to recharge enough power to turn the phone on. If the phone still does not turn on, then the battery or the charger may be faulty. Borrow someone else's charger and see if an alternate charger can get the battery to respond. Otherwise, you may need to replace the battery in your phone.
Resetting Through the Computer
If your phone is computer compatible (like the iPhone), use your computer to reset it through a USB cable. The phone may have come with a computer program when you purchased it. The program goes on your hard drive and will recognize and access your phone when the phone is connected to the computer via the USB cable. The iPhone uses iTunes for this purpose. Once the phone is plugged into the computer, access the program and click the "Restore" button. This can erase contacts, photos, calendars and other data but should restore your phone back to working order. It will also restore any information from the phone that you had previously backed-up on the computer, such as text messages and settings.