The subject line says it all.
Everything was working fine, then, out of the blue, this afternoon I have no more Intellisense in VS2012 Pro. I've tried resetting the Import and Export settings back to the default Visual C# Development Settings, but that did squat. Also my Solution Explorer pane doesn't explore my solution (no more file hierarchy).
What gives? I'm no IDE expert so I don't fiddle with the settings much. I just know this "ain't what it used to be" at all. I've Googled, I've failed to fix it.