Hagar,
It may sound confusing, but it all makes perfect sense to me. Just to summarise, here is the sequence of events to date:-
1. Installed fs9.1 update.
2. Installed No-CD Crack.
3. Experienced loss of a/c image in 'Create Flight' preview screen and suffered CTD on exit or minimize.
4. Deleted fs9.exe containing crack.
5. Installed original backup copy of fs9.exe. Problems persist.
6. Deleted original backup copy of fs9.exe.
7. Installed fresh copy of fs9.exe from FS2004 Disc1. Problems persist.
8. Created new fs9 desktop shortcut from fresh copy of fs9.exe (above). Problems persist.
9. Deleted all copies of fs9.exe, both in root file and in recycle bin. Deleted fs9 desktop shortcut. Deleted fs9.1 update.
10. Installed fresh copy of fs9.exe from FS2004 Disc1.
11. Created new fs9 desktop shortcut from fresh copy of fs9.exe (above). Problems persist.
12 Re-installed fs9.1 update. Problems persist.
So, if the 'No-CD' file was 'wrong' or corrupted, why do the symptoms persist when that crack (within the fs9.exe file at step.4) has been deleted and replaced with a 'good' copy?
Again, I ask the question: what other files - if any - could the 'N0-CD' crack tamper with? If it had potential to change other files then surely these other files will need replacing too?
"I'm not sure this is correct as I've never had to uninstall FS9."If you've never had to uninstal FS9 then count yourself lucky.
"If it's like other versions of FS uninstalling the sim will only remove default files leaving your addons right where they are." :-?

Assuming you have copies of every addon you've ever installed into FS9 and can spare the time to re-install them all over again. Anything you don't have a copy of will be deleted, because 'right where they are' is inside FS9. Unfortunately, re-installing the sim' won't automatically restore the gigabytes of addons and tweaks that I've painstakingly crafted over many months. This is the reason I wondered if it's possible to cut-and-paste most of the files into a fresh install and (hopefully) have them overwrite the default stuff (the very point that you and Gary seem to disagree on).
Andi