Check in the System Information (or System Profiler in older OS X systems), under the Bluetooth, and Wifi. Both should show the information for those devices, and not say something like "no hardware found"
Do the bluetooth and wifi cards show there as installed?
There are two connections on the bluetooth card, one is for the antenna, and the other is the data cable for bluetooth.
The bluetooth data cable also attaches to the interconnect board. Make sure that both ends of that bluetooth cable are securely connected.
THAT board (the interconnect board) may be your best choice for faulty connections.
Notice that your hard drive (and the optical drive) AND the bluetooth data cable all connect to that interconnect board. Check ALL connections on that board carefully. Make sure the board is seated completely to the logic board.
All that doesn't really explain the Wifi.
If all the connections seem to be properly connected (as far as you can tell), make sure that you try both SMC and PRAM resets.