Perform a soft reset as the first step in fixing a smartphone that won't turn on.
When your smartphone won't turn on, the first thing to try is to perform a soft reset. This process helps resolve minor software issues that may be causing the problem. It involves restarting the device without losing any data.
Example: For iPhones, you can perform a soft reset by pressing and holding the power button and either the volume up or volume down button simultaneously until you see the Apple logo.