Is this a new install or was everything working OK until now? If you have tried Holdem Manger in the past try the password 'postgrespass'. If that doesn't help click your Windows Start button then type the following command:
and click on it when it appears. Do you see the PostgreSQL service in the list? Is it started, or can you start it?
Then you probably didn't start PokerTracker 4 with the 'Logging Enabled' option on your Windows Start Menu. Click your Windows Start button then type 'PokerTracker 4' and you should see the 'PokerTracker 4 (Logging Enabled) option show in the menu.