Change Ini File Entry (Language)

Hello,

I have a program with multilanguage.
It save to "program.ini" [Language] [Set] 1 English 2 German
Example:

[Language]

Set=1  ;English

I want a small messagebox or I want if install sucess and finished
that a qustion German or English and set this in INI file.
Can NSIS this?

OR:

Question
Or delete program.ini
Rename german.ini to program.ini

Thank you...

I think an InstallOptions page giving the user an option would be a better idea. See Contrib\InstallOptions and Examples\Modern UI\InstallOptions.nsi for example. While installing, in a section for example, read the INI for the user's choice and write the value requested by the user.

If you still want a message box after the installation finishes, you can put it in .onInstSuccess.