Failed Emissions Test - Help!

My vehicle is a 2000 Dodge Stratus ES. My car passed the PA inspection but failed the emissions test. I was told to drive the car 100+ miles and return to the service center. I drove approximately 1000+ due to a trip and the vehicle still showed up as "Not Ready for Testing". I was told to drive the car some more and bring it back to the service center. I drove 500+ more miles and the car showed up as "Not Ready for Testing". Once again, I was told to drive the vehicle 100+ and return to the service center. I drove 500+ again and my car is still showed up "Not Ready for Testing". In the past 5 - 10 months, I've had a tune-up, new tires and alignment, oil changes every 3000 miles, etc. I do not know what is possible wrong with my car. I have consistently kept up on maintaining it. Please help me!

go to a shop and have them look at your car, see what the problem may be. Just something that you should know that not too many people know, at 50,000 mile intervals, you should replaced your oxygen sensor. that's $30 part could be the reason why your car is not ready for emissions testing. I'm not too sure about PA, but I know in Jacksonville, FL, there is an I/M 240 testing that tells you specifically what is wrong with your car if you fail. But definetly have your computer checked out to see if there are any faults.