Toyota Repair: Water inside the car, plastic pillar, car upholstery

Question
Ted--

  The car is a 1992 Camry.  After sitting outside (undriven) for about 3 or 4 months, a LARGE amount of water collected on the floor in front of the driver's seat ... so much that the carpet was SOPPING wet.  (And as an apparent result, the car interior is filled with mildew.)  There is no indication of leakage around the windshield or the moonroof or the door.

  Is there a drain hole somewhere under the vent at the base of the windshield that might be plugged, causing rain water to fill the vent and dump into the passenger compartment?  Without jacking up the car, I looked under the car near the driver side wheel well for a drain pipe, but couldn't see one.  Is there one?  Would blowing compressed air up one (if it exists) unblock it?  Or do you have any other thoughts of the cause and cure?

  Also, any suggestions on how to kill mildew in car upholstery?  

  Thanks.

Answer
There is a drain hole for the sunroof, open the sunroof and look for it at the left front corner, the most common problem is that the drain hose became disconnected just below the headliner or it is clogged up, try doing the following:
With the sunroof fully open take a bottle of water and pour into the sunroof drip rail slowly, if the water backs up and doesn't drain the drain hose is clogged up, in most cases the water will disappear into the drain hole and then run out in the passenger compartment if it's disconnected, if that's the case remove the sunvisor and the left plastic pillar cover and pull the headliner down to see if the plastic tubing is connected to the metal drain pipe.