You need to log onto windows embedded on your terminal as an administrator. I had to do this on a hp terminal recently and it was a pain to dig it out of the manual…
Administrator Logon Access
To access Administrator logon regardless of the state of the thin client user mode:
1. Click Start.
2. While holding down the left Shift key, click Log Off.
3. Still holding down the left Shift key, click Log Off in the confirmation window.
The screen for Administrator logon is displayed.
NOTE: The default password for the Administrator account is Administrator. The default user name
and password for the User account is User.
You can use the HP Windows Logon Manager to permanently modify the default login user. Located in
the Control Panel, only the Administrator can access this application.