Answer to: Reboots after replacing power and sensor cableTry powering it on with the replacement parts detached. If it boots normally, then acquire new replacement flex cables. If not- check for damage to the mother board.
Answer to: Why do I have a Black Spot on my Screen?Seems like your question has already been answered. You will need a replacement.
Answer to: replaced glass, home button sunkin in?As stated above- transfer the old home button flex cable from your original screen. Remove it carefully with an iSesamo or similar tool. Make sure you transfer the plastic ring that is adhered to the screen between the home gasket and the glass, as this will create sufficient spacing for it to function properly. Remove any old adhesive from the metal surfaces of the home button bracket; I like to attach the assembly to the new screen with Loctite superglue (it's the best I have found, and dries the quickest), and use a strip of thin double sided tape to run the flex cable across the bottom of the digitizer.