Same thing here, yesterday was able to log into dead rising 2, today could not play bulletstorm at all. kept getting an error claiming i was not able to log in due to firewall was blocking or network was not connected to internet... obviously thats incorrect or i'd not be posting this here.
contacted ambassador services and was lead here. just adding myself to the list of people having the issues. would like very much to connect to GFWL soon :3