Is your Windows/PostgreSQL using a Czech locale? If so you'd want to refer to
this link for further details. If not then locate and delete the postmaster.pid file if it is present (not "postmaster.opts" which may be there too). You can find that file in C:\Program Files\PostgreSQL\9.3\data\ although you may have a different PostgreSQL version (e.g. 8.4, 9.0) or have it installed in C:\Program Files (x86). Once it's deleted, reboot and try starting PokerTracker 4 again. If that does not fix things click your Windows Start button then type the following command:
services.msc
and click on it when it appears. Do you see the PostgreSQL service in the list? Is it started, or can you start it? If the service is listed but not starting open the Event Viewer (in the same way - if you type 'event' after clicking your start button you should see it). In the top left section, expand "Windows Logs" and click on "Application". Do you see any recent errors in the top center section for PostgreSQL? If you do let us know what they say.