2001 Ford Taurus staarter

I am having problems with the starter. I have removed it 3 times, and twice I have had it checked at a parts store, and it cam back good. I have also had the battery check and it is good. I cleaned up the area where the starter goes into the flywheel housing, to make sure I had a proper ground. I checked the voltage on the small wire that connects to the starter with a multimeter and it read.24. The place that I used for a ground point had some oil on it, so I may not have had a good ground to check it with. When I put the starter back in the care the last time, it started up, so I turned it off, then I tried to restart the car. The car started then died. When I tried to restart the car acted like the battery was dead, so I tried to jump start it, and nothing happened. Two attempts to start the car resulted in small clicks from the starter area. After three attempts to start the car, there was no sound at all.