IK has separated SampleTank and the sound content. Marketing most likely. The time limit is on downloads, they do encourage you to keep a copy of your installer.
I don't know what it's like to install on Windows,
Well, apparently neither do I. I downloded the sound content (a ZIP file), unzipped it and there were instruments and stuff in it like I was expecting, but when I ran the installer, it said "no sound content to install." I tried moving the files to places where I expected that they could be found (within the Sample Tank folder) but no go.
If they aren't going to supply manual installation instructions. at least the automatic installer should work. I dunno.