cannot install postgres

Dear All,
Once in a while I ever installed the old progreSQL, but then I uninstalled it.
Now, I want to install it again, but always asked for a password, when I enter the
password it will said that the password is wrong. 
What should I do so I can install it again?

Thanks in advance.

-- 
Best regards,

 -Sobari Tanuwijaya-

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along the same lines as the life of his Son...