If you have lost front camera and touch screen. The flex cable that sits inside the front panel is to be replaced. The flex cable is the one that has the sim card slot and the front camera module. I found that in the old flex cable was damaged at the portion where it is sliding in and out the metal housing. The thin circuits at the most outer edges of the flex strip appeared to be worn out on the left and right. I am guessing it is the circuit for the touch screen as well as the front camera.
Now both touch screen and front camera is working again
Tip. When removing the flex cable for servicing, be extremely careful moving the cable out of the front and middle housing.