Touch screen frozen, not responding at all

After replacing the iPhone 5 Front-Facing Camera and Sensor Cable, my touch screen became completely unresponsive. Took it apart again checked all connectors and sockets, but all looked okay. I figured that I damaged the screen in the repair so I ordered a new screen. When this arrived I installed the new screen, put everything back together, but still had the same problem. Next I took the unit to a gadget repair shop who tried one of their screens and still the problem existed. This we concluded that I must have fried the MB somehow due to static electricity, so I think end of story the phone goes in the drawer for spare parts. A few weeks later I am donated someone's old beat up 5, so I see an opportunity to replace the MB in my unit. I proceed with the exchange, put it back together and: "You got to be kidding me, still the same stupid issue". That night I gave up and finished my case of beer ;).

Today I'm thinking, lets quickly try my original screen. I did not want to go thru the addition of front camera, so I just connected the original screen with the 2 connectors, left the unit open, connected the battery and powered up. Holy Cow: IT WORKED! Now I take the other screen with the front camera connected, put this back on, but leave the front camera disconnected: IT STILL WORKS!

Conclusion: Turns out the original repair caused the issue by using a bad aftermarket Front-Facing Camera and Sensor Cable. I switched this out with the one from the donated beat up iPhone 5 and voila: I'm back in business :)

No need to answer my question as I already did, but I wanted to share my experience and hopefully prevent the frustration (not to mention wasted money on components I did not need) for others. Lesson: when changing a component and a seemingly unrelated issue occurs, look first at what you replaced (what changed)!