Work through these checks in order
Call or message the device, listen for notifications, connect it to power and check for vibration or sounds.
A device with an empty battery can look identical to a failed display. Charge it with known-working accessories.
Follow the forced-restart sequence for the exact model. This can clear a frozen interface without erasing data.
If the device rings, vibrates or is detected by a computer while the screen stays dark, the display path may be involved.
Cracks, liquid exposure, heat, impact damage or a lifting screen need qualified inspection rather than repeated restart attempts.
Before an erase, restore or repair decision
Confirm what data is backed up, what a reset or restore will remove, and whether you still need access to account credentials or authentication methods stored on the device.
When professional service makes sense
Hardware damage, repeated power failure, liquid exposure, battery swelling, damaged ports, broken displays and problems that persist after low-risk software checks can require qualified inspection.