A reply to a Tweet on #sqlhelp prompted me to look this up. The question was on finding out the SQL Server BINN folder path. This can be done using WMI in the following manner for SQL Server 2008:
strComputer = "."
Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\Microsoft\SqlServer\ComputerManagement10")
Set colItems = objWMIService.ExecQuery( _
"SELECT * FROM SqlService WHERE SQLServiceType = 1 and ServiceName = 'MSSQLSERVER'",,48)
For Each objItem in colItems
Wscript.Echo "-----------------------------------"
Wscript.Echo "SqlService instance"
Wscript.Echo "-----------------------------------"
Wscript.Echo "BinaryPath: " & MID(objItem.BinaryPath,1,InStr(objItem.BinaryPath,"sqlservr.exe")-1)
Next
The SQL Server 2008/R2 WMI namespace has visibility for SQL Server 2005 also. So the above snippet of code can be used to retrieve the BINN path (PathName property contains the fully qualified path to the service binary file that implements the service) for the SQL instance. You can change the SQLServiceType to a different value to get the Binary Path folder for other services as well. The value is the above code is set to 1 for the Database Engine. The ServiceName parameter can be used to filter down the results.
For a named instance, you would need to change the service name to MSSQL$INSTA if your instance is called INSTA.
The same is possible through the much talked about Powershell as well.
Other ways to do this would be to use the xp_instance_regread XSP which is not recommended as it is an undocumented command. An example is show here.
Thanks to @afernandez for pointing out another way through a CLR TVF.
TroubleshootingSQL 