I am new to these forums, I was wondering if someone has seen my problem before...

I have an Iphone 3g 16gb with a replaced front glass/digitizer. It was working great for a while (months) since the glass was replaced, but then yesterday, I noticed that the proximity sensor was not working. So, I opened up the phone again to see if something perhaps was blocking the sensor, or if the cable had become dislodged. Anyway, when I put it back together, it didn't boot up! So, I plugged it into my macbook, and itunes could still see it fine and sync with it, so I knew it was still "on". That being said, I tried to toggle the vibrate function just so see if it would vibrate and nothing, just a phone that appeared completely off, except for being able to see it in Itunes.

Next I tried flashing it with 2.2.1 back to factory defaults to see if that would fix it. Still nothing. The "geniuses" at the apple store wouldn't help me either, because apparently the water-sensitive tape at the bottom got wet at some point. I am sure it hasn't been wet or in water, at least for several months. So, what could it be? It's possible too that I damaged the LCD ribbon cable and/or proximity assembly. If either of those are bad, could it cause this behavior? I would think that even if one or both of those were bad, I would still feel the phone vibrate when I flip the side switch, since itunes sees it as "on".

Any help would be greatly appreciated....