can't connect to server on localhost

Hi

Last night i mailed a message about me not being able to install Postgresql 8.4.3 successfully on windows 7 professional.
I have since temporary quitted my antivirus and firewall programs and I could install successfull.
In the installation it askes you for a password which it uses for for the service account and it also uses the same password to secure the database.
It keeps telling me that my password is wrong. I know what my password is because I confirmed it.
It does this regardless of whether the anti virus and firewall are running or not.
I checked and yes the postgres service is running.

H.F.