Flickering screen/looping reboot and now dead

I had a flickering screen and the phone would continuously boot up, freeze at the Verizon logo and then reboot. After a few hours of this I turned it on and off a couple of times and then plugged it into my computer to charge (while off). The next morning I turned it on and it was fine. A day or so later I tried to take a picture. The instant I hit the picture button the phone went dead. I haven't gotten a peep out of it since.

I took it to the Verizon store and the guy behind the counter pulled a little piece of that blue 'tape' from between the two halves of the phone and said that was my problem. When I asked for clarification he mumbled somthing about a cable between the two halves and that the tape did something/kept it from doing something.

After getting the phone appart I looked at the cable and saw nothing wrong. I figured I'd see a tear, hole, or that it would be out of its connections a bit. Nothing.

So what really is/was wrong with my phone?

ETA: I should mention that I have the VX8500