Suddenly, "this song is not available" for all songs, over HDMI

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I use Spotify on my my laptop connected to an RCA flatscreen via HDMI. Everything worked fine for several months. After returning home from a 6 week trip, suddenly Spotify won't play anything, reporting the error "this song is not available..." for all songs. This only happens over HDMI (it plays fine over my laptop's lousy speakers). 

I have already uninstalled, restarted, and reinstalled Spotify. I have also switched to Speaker Device playback and set to 24bit/192kHz (that plays fine at any setting, actually), and then back to HDMI. I have also already turned off all Offline sources in Spotify preferences. I have also deleted the ".../appdata/roaming/etc." file which many people were talking about.

Nothing helps. Any ideas?

Plan

Premium

Country

Canada 

Device

ASUS G73JW Laptop

Operating System

Windows 7 x64