Register and run PostgreSQL 9.0 as Windows Service

Just run 'Command Prompt' as windows administrator and run the below command:

pg_ctl.exe register -N PostgreSQL -D "D:/Program Files/PostgreSQL/9.0.4/db_data"

You don't need to specify a User and Password, as previous answers have suggested.

Use the register parameter for the pg_ctl program.

The data directory should not be stored in Program Files, the location of %ProgramData% is e.g. a good choice.

pg_ctl.exe register -N PostgreSQL -U some_windows_username -P windows_password -D "%ProgramData%/db_data" ...

In newer versions of Postgres, a separate Windows account is no longer necessary, so the following is also sufficient

pg_ctl.exe register -N PostgreSQL -D "%ProgramData%/db_data" ...

Details are in the manual: http://www.postgresql.org/docs/current/static/app-pg-ctl.html

You need to make sure the directory D:/Program Files/PostgreSQL/9.0.4/db_data has the correct privileges for the windows user you specify with the -U flag.

Btw: it is a bad idea to store program data in Program Files. You should move the data directory somewhere outside of Program Files because Program Files is usually highly restricted for regular users - with a very good reason.