I phone 4 problem
How can l switch on phone 4
It can be taken to apple Center for service
How can l switch on phone 4
It can be taken to apple Center for service
It will need to be serviced/replaced, but I believe Apple no longer supports the iPhone 4. If you have an Apple store nearby, you can check with them, but you may need to find a third party repair shop.
Most folks would use the On/Off switch. If this doesn't work for you, you may need to provide more information.
On off switch is not woring
I phone 4 problem