Why psql.exe does not work?

Hello,

I have done a silent installation, the installation
worked eventually, and I can use pgAdmin interface to
connect to it. However I have problem using psql.exe
to connect to the database.

I need to create a database called delphie from
command line. It should be a part of the installation
I'm working on.

I used the follwing commands
psql.exe -U root

but it keeps giving me:
psql: FATAL: password authentication failed for user
"root"

root is the supper user and the password is also root,
but not only the program does not prompt for password
but also there is no way that I can supply a password
through the command line.

The ultimate goal is I need to create a database
automatically without user interacation. I have a sql
script that I need to run to create the tables. I have
used Oracle without problems before but not sure how
to approach with Postgres.

Any help/tip is greatly appreciaged.

Sean