I`ve just followed the tips on for when the corners of your screen arent operating properley. I loosened the screws off as directed and my screen was much better. Then i noticed my phone had no signal and then it was saying insert sim card.
I tried reinserting it a soft reset the whole lot. Nearly even did a full wipe!
It`s then i remembered what i`d just done. So i retightened my screws an voila signal again!
Just thought i`d post this just in case anyone else has the same problem i had...