I downloaded Dead Money the day it came out from Steam. I've played several characters through it. I went the load my character today it said,"Based on content no longer available, would you still like to load?" I exited NV, saw my Steam account was still logged in. I restarted steam, and loaded the NV launcher. I went into Data Files to make sure that Dead Money was still set to load. It doesn't even come up as an expansion. I have not made any hardware or software changes to my computer since the last time I played. What happened to my DLC?