Chosen Solution
I left my iphone and put it to sleep, and then half an hour later, I went to turn it back on again and it didn’t respond. During that time, the phone was in my pocket doing absolutely nothing. I have tried all of the solutions that I found online including the force restart, etc. I have tried plugging it into my computer to see if it recognizes it, and it doesn’t. I have tried charging it and it still does not do anything.
Replace battery first and check that you can find the clue what you have to do.
As Akash suggested, if you can remove the battery it will help. I would lift the screen and disconnect the battery, then plug the phone into a computer with iTunes installed. If the phone boots up with the battery disconnected, then the battery is likely the problem: follow this guide to replace it. If it doesn’t boot up, you should hopefully still get an error message of some description from iTunes. The error message should give you a better indication of what is wrong.
