MINIMUM REQUIREMENTS
OS: Windows Vista - Service Pack 1 / XP - Service Pack 3 Processor: Intel Core 2 Duo 1.8 Ghz, AMD Athlon X2 64 2.4 Ghz RAM: 1.5 GB Vista / 1 GB XP Hard Drive 16 GB Free Space Video Card: 256 MB Nvidia 7900 / 256 MB ATI
X1900
OR
Go to: http://www.gamesforwindows.com/en-US/Games/Pages/grandtheftautoiv.aspx