I have the same'ish issue, the only thing that is different is that my pc does NOT turn off it freezes up and there is nothing I can do besides hitting the power button. I used Sixlauncher before thinking that could be the problem, uninstalled it and manually downloaded all the files and patches and ran the game via the Beta Launcher, same thing happens after 5-10 minutes. PS. I uninstalled ARMA II and OA completely, deleted all Dayz files etc, clean install did not help and my drivers etc are up to date. PSS. Played for about 3-4 weeks without any problem (besides the usual)