Automatic database backup on Windows Machine

Hi,

I am a newbie at PostgreSQL. I am running PostgreSQL 8.0 on Windows
XP. I would like to automate my database backup (pg_dump, pg_dumpall).

I can't add it to scheduled tasks as Windows doesn't see my PostgreSQL
superuser account (it only sees the service a/c). Even if it did i
think there might be issues when it prompts for a password????. I am
logged into my machine as my Windows user name.

Can this be done?

King Regards,
Will