Taking the advice to re-install Trainz, and not to mess around with the installer in any way (even moving the screen) I did so, (I had no other programs running and the only intruption was an explorer window opening when I inserted disk 2) and it said it had installed sucessfully. However the problem is still there.
There is no routes, no engines, (I can still create a new route, but only with the basic tools (Topography etc.)), no textures nor tracks nor trains or consists.
Just looking around the files (Program Files > Auran > TRS2004), I tried running "ContentFoundry.exe" but it gave me an error message saying that trainz is not installed on this machine. Content Dispatcher works though. Inside the Engines folder, I found what appers to be a folder for each of the built in Locos, but inside them were only the config text files.
All re-running the installer does (with the program still installed) is prompt me if I want to completly "remove the selected application and all of it's components"
Currently I still have TRS2004 installed (build 668 version 2.0), though oddly enough Windows didn't tell me a new program had been installed upon me opening the (classic) start menu. (Though that could just be Vista being Vista.)
These are a few theories of my own about the issue:
1) Un-installing the program through Add/Remove programs dosen't work (as that is what I've done in the past.) So I may need to find a different way to uninstall Trainz.
2) To prevent piracy, I know there is a limit on how many times I can leagally install trainz. (I noticied a clause in the End User Licence Agreement that said I wasn't allowed x amount of times, but it didn't say it would prevent it.)
3) Perhaps some other remnant from another time is stopping the built in content from being installed (as I'm pretty sure the built in content is not there)
4) There's more than enough storage space on the computer so that can't be it.
5) After most of it's life on a different computer at a different (not so far away) location, Trainz has decided it doesn't want to move, so it has decided to be mean. (Not likely, but it did go from operating on Windows XP to Windows Vista)