GTA 4 In Parts

Part 1 – Part 2 – Part 3 – Part 4 – Part 5

Download ALL Parts One by One & then Extract Part 1 Using WinRar.
FIX
If the game is not launching download two .dll files and place them in your GTA IV install directory, where the GTAIV.exe is found. In case the links don’t work, they’re called wmvcore.dll and wmasf.dll.

wmvcore.dll File
wmasf.dll file