Phone dead, won't turn on, not recognized in iTunes, Take Apart?

Hi all,

My iPhone 4s just simply died. 3 days ago I finally updated to iOS 7. It seemed to work, but was really slow, and it would not make a sound when a message or call was received, despite the no ring button was not activated. Checked settings and turned phone off, (thinking turning it off rebooted!) still no ring or message sounds, and really slow. Erasing phone message took 1 1/2 minutes. 2 days ago I flew on a plane, and forgot to turn the phone off, or put it in airplane mode. When I tried to use it after the flight it was black, would not charge iTunes doe not see the phone (I suspect because it won't charge or turn on) and nothing has charged after 30hours of charging with 2 different chargers, and cables. Tried to clean charging connector on phone with compressed air

My problem is trying to figure out what is wrong. If I take it apart, are there physical thing/tests that would tell me/show me it is the battery, connector, ect? Or is there no hope?