As Al said, it depends. Windows doesn't have
a standard system. For instance, if I install
Regmon I'll just make a folder named "Sysinternals",
unzip regmon.exe into that, and make a shortcut
somewhere. There's no way for you to check whether
I have Regmon unless you scan the whole disk.
With Windows Installer you can list installed
software, but most software is not installed that
way, so it's not of much value.
The standard method aside from Windows Installer
is to register the program EXE under:
But that's not always done. The best method is
to research exactly how the software in question is
installed. If you don't have a specific program in mind
then see here for script samples that demonstrate the
pros and cons of different methods: http://www.jsware.net/jsware/scripts.php5#enumsoft
> How would I use code to check if an application is installed? Just look
> the *.exe in the expected location?