One that i have done quite a few of lately was drop damage iphone 6 and 6 plus with no touch. Customers come in for screen replacement of course. Most of these are touch IC chip issues and after talking to a friend with 1 way they did it, i decided to try my own method. Sure enough aside from 1 6+ that was bent pretty badly, all the others that i reflowed the the touch IC chip were recovered with no issues.

Possible LCD damage. Look at the screen under light for any lines in the LCD screen.

Drivers not compatible most often. Get a usb wifi adapter.