When I type anything into the Spotlight menu in the top right corner, I get the normal list of top results. But if I then click "Show All", or if I just go to the Finder and initiate a search there, it returns no results. The status bar says "Searching This Mac…" and I get the spinner in the corner, but it never goes away and never shows any results.
I have had Spotlight reindex my entire hard drive twice, and it doesn't help. Rebooting doesn't help either.