Hi fols every time i try to download a new a/c and install the textures for example a 737 800 texture the system seems to crash once i load it and want to fly this paticular type. im not sure why it says a fatal error occured and that fsx is restarting????? help!!

Most likely theres a file that doesnot work with fsx.
If your getting the fatal error window uncheck the restart box, so the sim doesn't keep restarting. Remove the add-on and try firing up the sim. If the sim still wont start than theres two things to do. First delete the fsx.cfg and any saved flights, see if the sim fires up, if not than try using the repair function. If none of these work than it looks like you might have to do a reinstall. When ever you add something to the sim always read the "read mes" carefully so you know what to do in case the addon don't work, and add one addon at a time. Also don't forget to always back up your files before changing them, good luck.