Wifi, Bluetooth won't work.
I'll start of with a brief history. I bought my Macbook Pro 15", 2.53 GHz 4 GB RAM (Mid 2009) in 2010. I bought this off a second hand dealer in my town, and basically it wasn't covered under warranty. It was working fine except for a little ding near the screen (on the top cover). Then, one day, a friend accidentally pushed the screen too far back and the display kind of got ripped out of the top casing. I tried gluing it back together but it didn't happen. I used it as it was for a while, until it the WiFi started getting spotty. If i used the wifi normally for a while, it would just drop off. Later, wifi would only work once i closed the lid and opened it again or restarted the machine. This went on for almost a year and a half. Recently, a year ago, the wifi just stopped working altogether, saying "Wifi : No hardware installed".
I took it to another service guy and he said the wifi chip needs to be replaced. He bought a new one and tried installing it, but it just wouldn't recognise a new wifi/bluetooth card.