Michael,
You can always "manually" uninstall!
1) save all your custom contetn (Details available by Search facility)
2) use Windows Explorer (as an adminitrator - modify the words if you're using Win 7/Vista etc).
3) navigate to the folder where trs 2010 is installed.
4) Check the folder properties - you need to set "read only" OFF
5) Delete the folder.
6) before you re install, tidy the registry (you may need to check Microsoft instructions for this).
I use "start" -> Run ; now type "regedit" (no quotes.
In the registry editor, remove all references to Trainz.
You can use CCleaner instead - it is more automated if you are concerned about editing the Registry.
7) once cleaned, re-install.
HTH
Colin