This is a simple replacement. If FAST LANE STUFF is installed, and no newer expansions/packs are installed, it will replace the load screen with the Base Game load screen.
If you want to replace it with any other pack's load screen, see this tutorial.
It's a really quick and easy process, but it's obnoxious for me to have to do it for every possible combination of installations.
ONLY USE if Fast Lane Stuff is the most recently released expansion/pack you have installed.