Postgres is installed using a secure password for the 'service' user under windows. It may be changed by the venue if they wish and if you do so, then you may need to:
- Find the local 'postgres' user on the computer using the Windows Administrative tools an edit the user id. You can change the password the way you would normally change the password for any other user (and is dependant on your version of windows)
- If you change the service password, then you must also open the 'services' control panel and find the postgres service. Change the password there as well. To confirm that you got it right, please stop and start the postgres server. if it stops and starts, its safe to bet that the server will restart on the next reboot of the server.