Search for File

Hello!
I'm just starting to write my first NSIS-Script. I want to write a Installer for a Addon for a Program.
The Script should search for the File "Application.exe" on all Harddrives. If the the File not found the Installer gives a Message and Close. Else the Installer take the Directory of the File as Installation-Path and install it.
I have search for a example, but i didn't find anything.
I hope anyone can give me a little Sample-Code.
Thanks for your Help
magoo2002de

Use this to search for a file on a specific HD:



And this to search for all available HDs:

Thanks for Links, kichik! But I really didn't understand the Scripts.
Can anyone give me a working Example Script?
Thanks!

Don't search for the file that's not very clean.
Use the uninstall string in registry to check if application is already installed.
Kind regards
Michael