PostgreSQL not working, pgAdmin always says server not listening

Question

I am brand new at this so maybe it's a simple mistake. I was given a very large .sql file with the instructions to make a copy of a database locally on a computer. I was told "to be able to install the database you need to install postgres. Use pgAdmin to create a table called reports with UTF8 encoding".

pgAdmin III always tells me the server is not listening. Postgres is not showing up anywhere in the services in administrative tools. Whenever I install or uninstall Postgres 9.1 or 9.2 I get errors. When I uninstall I get "Error stopping service postgresql-x64-9.2", "Error deleting service postgresql-x64-9.2", "The data directory (C:\Program Files\PostgreSQL\9.2\data) and service user account (NT AUTHORITY\NetworkService) has not been removed".

I was advised to login to the postgres account, however none appears at the login screen. If I try to create an account named postgres I get a bogus error message (see picture)

I was advised to type this into the command line:

When installing I get this error: