Options for installing a Service Application: /username=name Sets the user account to run the service under. You must also ...

Options for installing a Service Application: /username=name     Sets the user account to run the service under. You must also     specify the /password= option.  /password=pwd     Sets the password for the account to run the service under.  The /username and /password options will be used only if the vendor of the service designated it as requiring a user account. If a service was so designated, and you do not use the /username and /password options, you will be prompted at install time for the account. /unattended     Unattended install.  Will not prompt for username or password.