Why won't my iPhone 3G turn on?

It sounds like a dead logic board. Have you tried rebooting the iPhone by holding down the sleep/wake button and home button simultaneously?

"IPHONE Model: MC676LL RAM: 14GB (10.4 Avail)

CODE Ver: 4.2.6 (8E200)

PROB: Symptom: My Iphone went dead at work.

1)I tried plugging into the car charger thinking the battery was dead, but no charge and no charge indication = still dead.

2) I tried my home charger, (thinking it was the car charger) but I got the same symptom = still dead, nothing nada...

ACTION: I checked you tube and found this site

FIX:

1) I checked this site and came across the suggestion above to ""by holding down the sleep/wake button and home button simultaneously"" and it worked. I entered the security code and all is in order."

just hold power and home button ata a tym..........ur phone will restart with in 2 mins :)

Hold the power and the home batten for 10sec then release your hand on the power batten but still keep your hand on the home batten for about 4sec, release ur hand now, your iTunes should detect it now.

I had a similar problem, and mine turned out to be a loose connection from when I replaced the LCD. Once it was properly connected I had no problem turning it on.

"Totally bizarre guys. I GOT IT WORKING!!

Had the exact same issues as everyone else.

Thought it must be the battery. Changed it.

Tried to power on get the apple logo then disappears.

Tried holding power and navigation button screen blinks then nothing.

Tried this several times. Then it occurred to me.

Hold the power button on the apple logo comes up keep holding it till the apple logo goes away. WAIT for a few more seconds...

Now WHILST holding the power button STILL press and hold the navigation button and keep holding it.

It will then showup the apple logo again keep holding it....

The screen goes blank (it does not blink)

Then the connect to itunes screen comes up and its business as usual restore method.

Hope this helps people."