Password authentication failing

Hi
I installed Pgadmin3 version 1.12.3 on Linux Mint 12 which also has
PostgreSQL 8.4 installed.

It all worked fine and I was able to look at the database.
Then I went away for a few days, came back and now have a problem
connecting to PostgreSQL
the error is:
Error connecting to the server: FATAL: password authentication failed for
user "postgres"
FATAL: password authentication failed for user "postgres"

Seems simple enough! but I retype the password and no joy.
I have another application that uses PostgreSQL (LedgerSMB) and it works
fine.

After some research I changed the password using :
ALTER USER postgres PASSWORD 'newPassword';
in psql
this also does not work

I also edited pg_hba.comf and replaced the word 'ident' with 'trust' in the
first line.
I restarted the postgres server and still no joy.

There has to be something simple that I am missing but I can't see it!
any help would be appreciated

thanks

Bill