Forgotten Password

Hi, I installed PostgreSQL in my PC (windows XP) a few weeks ago and I
can´t remember the password for the user 'postgres' so I can't access
the local database. I can uninstall PostgreSQL but I don't know if I
will be able to reinstall it since I have the McAfee antivirus
installed. Is there a super user in PostgreSQL I can use to change the
passwords? Is there another solution?
Thank You.

--
Juan Pablo Hernández
CIMA - UTFSM
Av. España 1680, Valparaíso, CHILE
www.cima.utfsm.cl
Teléfono: (56)(32) 654-712
Fax: (56)(32) 654-714
juanpablo.hernandez@usm.cl