Complete installation instructions and system requirements are detailed in the "Installing SQL Server" section in SQL Server 2005 Books Online. You can access the complete Setup documentation before you install SQL Server 2005.
To view Setup documentation:
Navigate to the root of the installation media or to the directory that contains the extracted product installation files.
Navigate to the \Setup\help\XXXX subfolder, where XXXX is the four-digit language designator.
Launch Setupsql9.chm.
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