Ok, let's start again :
The PC I am working on does not have internet ... It will have later.
1) I installed Visual C++ NOT SP1 on my computer (I installed all other needed component too : DirectX ... and son on)
2) I copied the C++ installation files in the temp MediaPortal installation directory, so that MP feel like having the files.
3) Tried to install Media portal ... But when I get to what I have to install, it kept on repeating "Visual C++ 2005" not installed.
I click on install, and it installs the old Visual C++ (That I copied before, manually to the directoy) ... but when it ends, it kept on saying that visual C++ is not installed.
4) I try to see what happens, so I launch a regmon, and checks what MP installer is looking for. MP is simply looking in the "uninstall" folder (HKLM). But since I did not install the right version of Visual C++, the ID of the installation of visual C++ is not the same as the one mediaportal is looking for.
5) So I downloaded the latest Visual C++ files (SP1) ... Installed it ... and all went well afterwards
It is hard for me to take a screenshot, since I would have to uninstall MP and Visual C++ SP1 of the computer.