Hi there! Quite coincidentally, I just performed a re-install of my FSX on my Windows 8 OS a few minutes ago.
There are a few things you should do before you attempt a re-install.
-> Create a backup of all your FSX planes and helicopters in another file and place it somewhere like on the desktop.
-> Uninstall all your add-on Aircraft and maybe scenery.
*Bear in mind that although you have removed FSX, FSX Acceleration is still in your system and has to be removed from the 'Programs and Features' category in the Control Panel.
** My FSX version is FSX Gold, hence I have FSX Deluxe + FSX Acceleration. As far as I know, Windows 8 only supports FSX Gold, and players that do not have FSX Gold have said that FSX does not run on Windows 8. I don't know if it is true, as I have never tried it before.
Now, if your FSX is FSX Acceleration like mine, you must have 4 things:
- FSX Disc 1
- FSX Disc 2
- FSX Acceleration
- Product Key for FSX Acceleration
- Product Key for FSX Deluxe (Optional)
Here are the steps for the re-install:
1. Put Disc 1 into your disc drive. Run it.
2. Choose the option "Remove FSX" instead of "Repair FSX".
3. The removal will start, but somewhere in the middle, the removal will pause, and you will be prompted to remove Disc 1, and put in Disc 2. Do so accordingly.
4. Disc 2 will remove most of the files from your Local Disk.
5. Now remove Disc 2, and uninstall FSX Acceleration, if you have it.
6. After removing everything, head back to your main FSX Folder (Microsoft Flight Simulator X) in your Local Disk. Some files should still be there.
7. Delete the entire file.
8. Now, run Disc 1 again, and Install FSX.
9. Somewhere into the installation, there will be another prompt to put in Disc 2. Do so accordingly. The installation will resume.
10. Disc 2 will end the installation. Now, immediately remove Disc 2 from your disc drive and put in FSX Acceleration. This will install FSX Acceleration.
11. Now, after the installation of FSX Acceleration, run FSX from the main FSX folder in your Local Disk.
12. While loading, they will prompt you to activate the game. *** If the you installed and uninstalled, and reinstalled FSX in the same PC, and you entered in the Product Key, the Key will STILL WORK, even if you uninstalled and reinstalled it. *** If you done so in another PC, I do not know how to help you.
13. The game will be activated, and you can play the game.
Hope this helps.

ThaddeusHWJ