Just reinstall all. You can have more than 1 version installed in your pc. I have the original game in one folder and 1.42 in another. This is what I did:
1: Install original game
2: Copy the folder of the original game on desktop, you can name it "A" for example.
3: Unistall the game in control panel/programs
4: Copy the folder "A" and paste as "B"
5: Install destination paris 1.42 in the folder "B"
6: Uninstall 1.42 in control panel/uninstall programs
The key is uninstall everything in the list of programs, but keep all files. With this trick you can have infinite versions of the game, and also is portable, you could run the game in a usb everywhere.