The serial number used to activate "Grand Theft Auto IV" is located in different places, depending on how you purchased the game. Finding a serial number is required when installing or reinstalling a game to a game console. If you installed the game via Steam, check the Library tab for the serial number, and if you purchased a hard copy, then it should be in the manual that came with the CD.Continue Reading
Load up Steam if it isn't running. Select the Library tab. Right-click on the game, and select "View Game CD Key." A pop-up displays the serial number.
Find the original manual to the game. Look on the back cover to locate the serial number.
If an activated version of "Grand Theft Auto IV" is installed on your computer, you can recover the serial number by using product key-finding software. Use a program such as Magical Jelly Bean Keyfinder or Winkeyfinder to recover this information.