Before you start re-installation process and if you are still able to connect to the database please EXPORT all of your hands and tournament summaries.
Preper your Poker Tracker 4 license numbers.
If your are using any additional settings in your PT4 please backup them as well. You will find tutorial on how to do that HERE
Step 1 - uninstalling PT4
1) Go to control panel - uninstall programs.
2) Choose and uninstall PokerTracker4.
3) Go to C:\ProgramFiles(x86) and delete that folder.
4) For this part you will need to be able to see hidden files in order to do it please check this link: https://www.howtogeek.com/howto/windows-vista/show-hidden-files-and-folders-in-windows-vista/
When you are able to see hidden files and folders go to: C:\Users\"your user name"\Appdata\Local and delete PokerTracker4 folder.
Step 2 - uninstalling database
1) Go to control panel - uninstall programs
2) Choose and uninstall postgresql.
2a) You will face 'postgresql data has not been deleted' -Go to C:/Program Files folder, choose PostgreSQL folder - delete it manuall
Step 3 - installing new version of PT4 and database
1) Please downlaod and install the newest version of Poker Tracker 4 https://www.pokertracker.com/
2)Follow all steps as they go - PT4 will install Postrgesql ver. 9.3.9
Step 4 - re-importing HandHistory
After you finish with all of those steps please do not update your PT4 and database version unless we ask you to do so.