jonileponce
Since it looks like you'll have to replace your failing hdd, you might as well consider going for an SSD upgrade and clean install Windows on it.
Good luck.(y)
Cutieful
Your laptop most probably has onboard (soldered) 4GB RAM.
Did you check if the old 4GB stick is working/good condition? It's possible that the old 4GB RAM stick is faulty or defective hence only 4GB is shown initially and what was...