I replaced my screen a few days ago. Worked out fine. Today, I noticed some dust inside. Took it apart to clean it. Put it back together, and there is NO cell signal at all on my phone. It's even asking me to pick what time zone I'm in because it can't figure it out. What can I do? I took it apart AGAIN, unhooked and then rehooked in the ribbon cables, but still no signal :\ where in the phone is the antenna? Please help!