Could you please indicate what the files are when you say default shaders (do you mean the Halo for example)
No, that would be default textures, and KLAX runway lights don't use them, so they won't be affected by an addon that change textures. Default shaders are those files in the FSX\ShadersHLSL folder, I guess the only way to restore them is to remove the folder and REPAIR the FSX installation.
The reason I ask is Ive spent the whole day UNinstalling ALL your Airports, GSX and the addon manager and Couatl...
That wasn't necessary, nothing of this is related to the Addon Manager or Couatl, except the PAPI flashing, but not the actual display of it (its appearance)
2) I then restarted Couatl from the addons menu in FSX, and then the PAPI lights sprung into action,..........and the Runway lighting was visible (but only very faint as before.
Faint lights don't have anything to do with any of our software, if KLAX is installed using its own installer, everything needed will be installed as well.
Ive also installed KORD as a test and the ALL the lighting is NORMAL as you would expect, and after I UNINSTALLED KLAX again the default KLAX lighting was Normal as expected
Of course, KLAX is the only scenery that has 100% custom runway lights made that way.
The last thing I want to do is Re-Installing FSX AGAIN so Ive attached some pics just to see if you can suggest anything. Just as a point of reference the Lights when displayed could be described as Tiny but very Clean, Sharp looking and as mention previously they appear orangy/bronze in colour.
I understand exactly the problem, other than being sure it doesn't have anything to do with our software, I can't say more. You must have installed something else that is affecting it, that we didn't know until now. Note that, you can't be 100% sure that uninstalling will restore ALL modified files, this is really depending on the uninstaller, the only sure way that everything is back to normal, is to reinstall FSX, possibly after removing its folder.
Another thing you might try, is to remove the %APPDATA%\Microsoft\FSX.CFG file, this will force FSX to start with a default settings file.