Reverse Thrusters

Hello, I just reloaded FS2002 Pro on my computer, everything seemed to be okay except my reverse thrusters are not working properly. I do get them to come on (all inications that they are working) but the aircraft (all aircraft) are not slowing down or stopping. I have changed settings in the aircraft.cfg files to increase reverse thrust, and nothing happens. I have calibrated my flight yoke with FSUIPC, and still no good. I spent 2 days reloading the simulator with all of my addons, I would hate to do another reload. If somebody can give me an insite as to what is wrong I would appreciate it. Thanks J.R.