I don't understand the problem. First, I deleted everything from the AC folder in Program Files, Drive C. Then I downloaded Javelin from their website using the link from EA. Without Javelin installed, I installed the entire game via Steam, but I changed the drive [partition to a different one]. Then, when I tried to launch it, it said Javelin wasn't there. So I uninstalled all the games and installed it twice on the Javelin. Then some errors popped up—first 1802, then 5702—and finally it installed on the Javelin. I restarted the PC and so far it's working... everything as an administrator and with Win 8 optimization disabled. But I can't guarantee this, as it might be pure coincidence. In the meantime, I force-ran the Javelin service via services.msc. First, it said it was missing and "scheduled for removal." Then, after restarting the PC, it happily launched itself with a manual signature. I'm posting this description, maybe it will help someone..
