Bad serial number given in setup - use this thread for help in ARMA 2 & OA - TROUBLESHOOTING Posted July 17, 2012 I also purchased the combined operations from Steam yesterday. the weekend special Arma 2 Combined operations. Both games appeared to install OK. BUT- When launching the 1st game, Arma 2, it gives an error message "bad serial number in setup" and just fails to start. The 2nd game "Arma 2 Operation arrowhead" runs fine with no problems. System - Windows 7 64bit ultimate OS QUESTION - how do you run Steam "as administrator" in Windows 7 ?