Hiii Sir,
i am dell inspiron 5523 15z laptop. before somedays due to issue in my powershare port dell replaced my motherboard. but after replacing the motherboard the i am able to find my warrenty and many other thing in my dell as well as service tag field is also empty in the bios. Technicains check out everything but he was not able to find where to enter it and no dell executive were able to solve the problem so if u have any solutions pls reply me.