Well, I dunno where you've gone wrong, it appears between (obviously, its alphabetical!!) inf & L2schemas folders, usually after inf on every windows system I've ever laid my hands on. If you ever have any issues un-installing software, you've deleted the folder, and trust me, you can, it looks like you have. Also none of the other hidden stuff shows in your Windows folder picture. See if I can search a picture on the net.
I'm a bit confused Arc, you got a ribbon of badges under your name, gfx team badge, gold member badge and a seven guru badge and you've never heard/seen the Installer folder?