>How can I check programatically if I have MSDE or MSSQL installed? I want to have 2 differente routnes in my system depending on the host database, but both reply MSSQlserver when I query the ODBC driver. Any help?

You can check for string 'desktop engine' in the global variable @@VERSION.

SELECT CASE CHARINDEX('DESKTOP ENGINE', UPPER(@@VERSION)) 
	When 0 Then 'MSSQL'
	Else 'MSDE '
	END