If you have the "Application was unable to start correctly (0xc000005)." error you can try the following:

1. Go to your GTA IV main folder.

2. Right click "GTAIV.exe" and go to properties.

3. Go to the compatibility tab.

4. Enable the option "Disable fullscreen optimizations".

5. Launch "Launch-/PlayGTAIV.exe".


If your game doesn't launch:
Try to rename/move your modded IV copy