I have a silent installation of SQL Server 2005 that works great when installing SQL Server on a machine that does not have it already installed. I use the following parameters when I perform the installation:

#define SQL_SILENT                    "/passive /qb"
#define SQL_USERNAME                  "username=MyUserName"
#define SQL_COMPANYNAME               "companyname=MyCompanyName"
#define SQL_ADDLOCAL                  "ADDLOCAL=SQL_Engine"
#define SQL_UPGRADE                   ""
#define SQL_DISABLENETWORKPROTOCOLS   "disablenetworkprotocols=0"
#define SQL_INSTANCENAME              "instancename=MYSQLINSTANCE"
#define SQL_SQLAUTOSTART              "SQLAUTOSTART=1"
#define SQL_SECURITYMODE              "SECURITYMODE=SQL"
#define SQL_SAPWD                     "SAPWD=StrongPassword"
#define SQL_SQLACCOUNT                "SQLACCOUNT="""""
#define SQL_SQLPASSWORD               "SQLPASSWORD="""""

It installs the instance of SQL Server Express without a problem. However, when I attempt to install SQL Server on a machine that already has another instance with components I get the following error:

*"A component that you have specified in the ADD_LOCAL property is already installed. To upgrade the existing component, refer to the template.ini and set the UPGRADE property to the name of the component."*

I have also tried using the UPGRADE method as per the error message

#define SQL_UPGRADE       "UPGRADE=SQL_Engine INSTANCENAME=MYSQLINSTANCE"

but get the following error:

"SQL Server Setup cannot perform the upgrade because the component is not installed on the computer. To proceed, verify the component to be upgraded in currently installed, and that the component to be upgraded is specified in the ADDLOCAL property."

Does anyone have any suggestions?

Thank you