i have a PowerBook G4 and was using it via wireless networks with no problem ...then yesterday it fell on the floor and now its saying there is no AirPort Card installed....did the card come out of place when it dropped ? h

Yes, it might have worked loose. hard to check from here, did you have a look?

For the Aluminum line,it's easy for the card to become dislodged if the Powerbook falls on its right edge (as you look at the screen). The card is dead simple to access from below.Just remove the battery, and you can see the card. Push the connector closed. All done.

If it's a Titanium, you can check ifixit.com for directions on accessing the card, but it's much less likely to disconnect, so I'm guessing you have the Al model.