asking for login name on install

[G.]

I am trying to install Natty on an older Acer desktop.  When I I try
the program to see if things work I get a login screen which asks for
a login name.  I have no idea what login name to use.  I have
installed Ubuntu 12 times or more and never had this happen.  I
checked the disk for defects.  This happens whether I use a USB or CD
that I burned.  I even downloaded Natty again just this morning.

Any ideas?

thanks


garyk