install directory append folder

Hello, I am wondering how to append a folder to the install directory. Default install directory is set with:

InstallDir "$PROGRAMFILES\${SMPROGRAM_FOLDER}\"

which is correct. My problem is when a user chooses a non default directory, say D:\ If they choose this, the install button is disabled, and they are unable to install. How can I, if someone chooses D:\ automatically show D:\newDir and install it there, like for example DivX do?

Thanks.

ps. everything else is installed like this:

; The stuff to install
Section "-hidden Main Application"
SetOutPath $INSTDIR
.....
.......
......
......


SectionEnd

and also one more thing, how do you launch a website at the end of the installation?

Cheers

1. Remove the \ off the end.
2. ExecShell open http://...
Put in .onInstSuccess

Stu

perfect. thanking you.