girlfriends older windows 7 dell inspiron 5040N keeps "saying" local network cable unplugged" but its plugged in, swapped functioning cables with another laptop with no help. had a good local repair guy for cheep but he is gone. i have replaced " stuff" inside other laptops + wondering if the part where the RJ45 cable end plugs into could be bad. not very savvy but usually get buy using another functioning laptop answering questions