So I have been using P3Dv3. I had installed Aerosoft's London Heathrow Mega Airport and the sim was running absolutely fine.
I decided to move the two London Heathrow Airport files to the top of my scenery library. The entry's were something like "Mega airport Heathrow" and "Mega airport Heathrow terrain".
I now get this message when I start up the sim:

I have uninstalled Heathrow to no luck.
I click on "OK" and the splash screen loads and then disappears. The actual sim doesn't load at all. I can't get it so start up!
Any help would be appreciated. Thanks.