sometimes i think widnows doesn't really disable stuff when they say its disabled. i installed microsoft security essentials (since the windows 8 was validated, i figure why not try it?
), even when i disabled it, it crashed gta IV EVERYTIME i played it. after the third time, i uninstalled it. problem gone. i5 750? it has hyperthreading? http://www.cpu-world.com/CPUs/Core_i5/Inte...0605I5750).html
maybe gta IV recognizes it differently than older intel CPUs, i don't know.