Get a magnifying glass and a flash light, remove the CPU/RAM Card and check the connector closest to the cage and check if the plastic is cracked. Since I use a CF to IDE - SSD on one of my Wallstreets, I've see the drive connector just pop off the mobo connector several times, but that's because the CF-IDE Adapter has no screws to hold down on to the HD Cage so it just floats there.

Hopefully connector on the mobo is fine, you really need to push down on it until you feel it go pop into place with your fingers. If not the connector is not fully seated in place. And tighten the hold down screws down to hand tight and no more. You will strip the screw anchor off the board if you over leverage it. (I did that with an iBook G4.... Damn my super strength!)