Installing with Inno

Hi, I made a skin for an application not written by me, which contains a modified executable with different Fonts (I know people frown upon that here, but it's done with permission from the software creator) and a folder with all the skin images.

These are the files I have:

Original executable + original folder with images
New executable + new folder with images

I'd like to install it with Inno, but I have a few problems.

1) The user has to specify the installation folder of the already installed application.
2) Check if the executable is present in that folder and if it is the correct version.
3) The user has to specify if the new skin needs to be installed or the original version.
4) Depending on the selected option, place the new executable/Image folder in the installation folder. The executable should be overwitten. The original folder with images should be removed first or else there'll be a lot of unnecessary images in the folder.

How can I do number 2, 3 and 4?
I think I need to create a custom script for this, but I couldn't find what I need in the Inno Documentation.

It should not be added to "Add / Remove Programs", because the application already has an uninstaller.

If anybody can point me in the right direction, then that would be great.

Yes, you need to create a custom script for what you want to do using the [Code] section.

If you use the same AppID you will not need to:

1 - Find the previous installation. Inno Setup will find it.
2 - It will not add anything to the Add / Remove Programs.

Thanks randem. How do I find out what the AppID is, because I didn't make the original installer?

You don't have the original script? You would have set it there.

No, unfortunately I don't have the script. The original installer was made by someone else with nsis and I'm using inno.

Then you don't have an APPID so to speak, that is only for Inno Setup. For future threads you should be more explicit in what you currently have and what you want to achieve. It would help in the direction of the help.

You can still do it but you will have to do the research on how that particular software is detected and where it was installed.