halls gap

I am getting a new computer this week and would like some info please, the specs are: Intel Core 2 Quad Q6600 8MB 2.4 Ghz 2G DDR II 800 Mhz Geforce 8800GTX 768 mb 2 x 320G HDD This system should have the power to run Arma well but this system comes with Windows Vista and I need to know if there will be an issue with Vista. Or is there any fixes people have found to fix the Vista problem or should I get the shop to install XP Home addition before it is too late. Any help would be appreciated.