Originally Posted by IGN.com
How many times can I install and uninstall GTA IV using the retail disc I purchased?
Rockstar: As many times as you would like, if using the retail disc version.
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Will I need the disc in the drive at all times?
Rockstar: To launch and play the GTA IV retail version, you must have GTA IV Disc 1 in the drive. If you want to play without a disk in the drive, you should buy the digital version of the game.
Will the downloaded digital distribution version of the game come with any different type of DRM than the retail version?
Rockstar: All versions of the game will use SecuROM for Product Activation. Downloadable versions of the game will have additional code if the vendor requires it, such as Valve's Steam program.
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I have several machines, including a large rig at home, in my office, and a laptop that I take on the road. Can I install the game on all of my machines at once, and if so, how many?
Rockstar: Yes. If you have the retail disc version you will just need to take the disc with you and you can play on an unlimited number of machines. For the digital download versions, each digital download vendor has its own policy on the number of installations that are allowed. Check the vendor's policy before you purchase.