this reminds me of something that happened to me a couple days ago.
So I got my hands on a Treo 650, courtesy a fellow webOS nation member.
I took it apart to clean and reassembled it to find out that the screen didn't work. After a couple tries, i was sad and proclaimed the display dead. I picked up another on eBay to plunder for parts, and the screen from that one seemed to have broke too. I was at a loss, wondering how it/I could have broken two displays?
Went on youtube, maybe someone had this problem before, and lo and behold, there was a comment on one video: "Excellent. I thought my new screen wasn't working but this showed me that the ribbon cable needs a bit of a push." I had nothing to lose so I gave the ribbon connector a hefty push and *click*.
I now (awkwardly) have two fully functional Treos.