Installing SQL Server 2005 Standard Edition on Windows XP will be failed.
Installation of MSXML 6 Service Pack 2 (KB954459) failed because a higher version already exists on the machine.
Solutions:
Using Windows Installer CleanUp utility to remove references to MSXML 6.0 Service Pack 2.
http://support.microsoft.com/kb/290301
Install SQL Server 2005 on Windows xp.
