During a test intall of SD7 I left the default admin user during the installation and did not create a new one. The Implementation Guide says:
Add New AdminUser:
Lets you create a ServiceDesk administrator account. When
you click this link, define the administrator on the Add New
AdminUser dialog box, and then click Save User to return to
the installation.
If you do not create the administrator account now, you must
use the default administrator account to log on to ServiceDesk
for the first time.
I think the default one was admin@ (something) and I don't know what the password was. Does anybody know?