When SQL Server Setup tries to install MSXML 6.0 SP2, it detects that the version of MSXML 6.0 is already installed on the computer. Therefore, the validation process indicates that the current version of MSXML 6.0 should not be replaced. This stops the installation of both MSXML 6.0 and SQL Server 2005.
To fix his problem, follow these steps:
1. Download the Windows Installer CleanUp utility from the below link
2. Run the Windows Installer CleanUp utility.
3. Select MSXML6 Service Pack 2 (KB954459) [6.20.1099.0] in the list, and then click Remove.
4. Install SQL Server 2005.
