One possible cause for Pro Tools taking an extremely long time to launch (on Windows) is if you happen to have a CD/DVD in your CD/DVD drive, and possibly if you have a mounted ISO.
Simply remove/unmount the disc, and Pro Tools should launch normally.
This short video will walk you through the problem
Pro Tools 12 gives us the ability to you our integrated Windows audio! This is a great new feature for Windows users. This means you won't have to use an ASIO interface, or an ASIO driver like ASIO4ALL.
This video shows exactly how to take advantage of this great new feature in Pro Tools 12
This video will walk you through the process of registering Pro Tools 12 to your Avid.com account, show you the files you need to download, and how to install and activate your iLok license.