mark767 wrote on Aug 11^th, 2014 at 10:18pm:

Well I just purchased FSX Gold.  I have not reinstalled FSX in about 3 or 4 years so I am probably due.  I was just looking through my installed aircraft and scenery and there is a lot of stuff I can get rid of.  2 or 3 nights of pain and I should be up and running with a working 727.

You could/should get away with just installing the Acceleration from the included disk, but if you need to install the whole lot, it shouldn't affect too much. Open the Windows RUN command and enter %AppData%\Microsoft\FSX, find and copy the fsx.cfg and dll.xml files and  then paste them somewhere safe (like the desktop). Uninstall FSX, then install FSX old. Copy your  fsx.cfg and dll.xml files and paste them back in the %AppData%\Microsoft\FSX folder and you should be fine with the change. You will need to redo any changes to you control settings, but because thre are some changes from the FSX to Acceleration button/keys commands, I do not recommend backing up the Controls\standard.XML file!