Systems Management

I would like to whitelist applications and have been looking at using Group Policy to achieve this. If you have done this, did you use the hash value, the file path, or the registry key to allow a specific app to run?

Basically I would like to block all applications and create policies by department that only allows the necessary applications to be allowed to launch. I noticed if I use the file path, then on the computer I can launch the app if I go to the exact path, but cannot launch it if I go to Start - Programs - and the app location.

If anyone has suggestions on how this should be done or how you have used group policy to whitelist, I would appreciat it!

Thanks!