Let's say I have two folders on the desktop: Computer and Folder1. If I double click Computer, the Computer folder is opened in an Explorer window. If I then double click Folder1, the Explorer window then navigates to Folder1, instead of opening a new Explorer window. I'd much rather have two Explorer windows at that point.
In folder options, I've set Browse Folders to "Open each folder in its own window" and [under the view tab] checked the box for "Launch folder windows in a separate process". But I'm still getting new folders opened in the same Explorer window.
I'm pretty sure that Windows wasn't doing this originally, but I can't think of what I might have changed. I certainly haven't been editing the registry or anything, although I'm aware that an update may have.