We currently offer a massive range of downloads for FSX, as well as older flight simulator add-ons for the ever-popular FS2004, FS2002, CFS3 and now becoming ever popular with dediced virtual aviators is Laminar Research's X-Plane series.
First, it is very important to read the readme file within the .zip package. Second, if you replace a panel with a new one, make sure you backup the contents of the panel folder of the aircraft you work on before you proceed. Copy the contents of the panel folder within the .zip package to the panel folder of the aircraft you work on. If there is a gauges folder, copy the contents to the main gauges folder located in "/Flight Simulator 9", unless it has been specified otherwise in the readme file.