It is strongly recommended to disable any security or antivirus program before extracting or installation of the game.If packed file require password its always.
Extract the zip file using WinRAR or WinZip or by default Windows command.How to Install Grand Theft Auto Vice City PC Game Setup Type: Offline Installer / Full Standalone Setup.(because of constant update from back-end file size or name may vary) Download File Name: _Gta_Vice_City.zip.