In many laptops, the wifi component is actually a rather small piece not integrated into the motherboard. It's usually about 1 1/2 inches square, and is connected to the motherboard by a couple of wires. It's possible these wires are loose or broken.
Check in the device manager and see if the wifi adapter is still listed. Don't confuse it with the listing for the on-board LAN, that's a separate listing in the device manager.