How can I confirm whether a SQL Server installation is 32 or x64 bit?

How about to confirm the component type when a particular SQL Server 2005 instance has been installed?

You can obtain the relevant information using a TSQL statement or referring to the SQL installation directory on that Windows server. Each of these options are outlined below:

Transact-SQL statement:

Execute select @@version from Query Editor or Query Analyzer and the results will be :

SQL 90

Microsoft SQL Server 2005 - 9.00.2153.00 (X64) May 9 2006 13:58:37 Copyright (c) 1988-2005 Microsoft Corporation Standard Edition (64-bit) on Windows NT 5.2 (Build 3790: Service Pack 1)

Microsoft SQL Server 2005 - 9.00.2047.00 (Intel X86) Apr 14 2006 01:12:25 Copyright (c) 1988-2005 Microsoft CorporationStandard Edition on Windows NT 5.2 (Build 3790: Service Pack 1)

SQL 80

Microsoft SQL Server  2000 - 8.00.2148 (Intel X86)  Jul  7 2005 20:33:10  Copyright (c) 1988-2003 Microsoft Corporation Standard Edition on Windows NT 5.0 (Build 2195: Service Pack 4)

If the installation is 32 bit then as highlighted above you will see 'Intel X86', if not then you will see 'X64' after the SQL Server version number.

SQL Server Installation Directory:

The default installation directory for SQL Server is \Program Files\ and the same can be referenced as below on a x64 operating system:

C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Binn

32-bit:
C:\Program Files (x86)\Microsoft SQL Server\MSSQL.1\MSSQL\Binn

For more information on the SQL Server 2005 x64 bit refer to the links: http://www.microsoft.com/sql/editions/64bit/default.mspx & http://www.microsoft.com/sql/editions/64bit/overview.mspx.