When I plug in the dongle it tries to connect, with its LED flashing blue and the dongle and its International Mobile Equipment Identify (IMEI) number visible in Ubuntu.
However, the Network Manager reveals that the point-to-point modem connection isn't configured, and I'm unable to manually configure this without an administrator password.
Since my password doesn't work, I assume this must be one Dell has set. A Farrell
HELPROOM ANSWER You need the root password, rather than one you have set up. Usually with Ubuntu this will be the password you gave your user account. If this doesn't work then you should contact Dell.