If you can access the Internet externally (friend's house, Internet café, etc.), or via another PC in the same location that may have different firewall restrictions, you can perform steps needed to complete a 'manual activation' of the game. Known conditions that may necessitate a 'Manual Activation' of the game:

In cases where an 'Online Activation' cannot be performed, one or more conditions may be prohibiting this (see below), and 'Manual Activation' will need to be performed. 'Activation' is a mandatory process for all installations of GTA IV PC, regardless of format. Welcome to the Manual 'Product Activation' guide for GTA IV PCĭuring typical installations of GTA IV PC, users that have an active Internet connection will be prompted to perform an 'Online Activation' of the game. Click HERE to return to Main 'GTA IV Activation' Site