Brand new PC all new components, Core i5 + 4GB ram + HD5770 + Win7 Ultimate 64 bit.
Inserted ArmA disc, ran autorun as administrator. Installed ArmA. Launched, set vid card options, played bootcamp for a while. Exited. Downloaded 1.04 patch. Ran patch exe as administrator. Launched, set new vid card options, played armory for a while.
Easy breasy no problems whatsoever. :)