PokerTracker

I reinstalled my postgres so I could have setup wizard. I installed 8.4 version for windows, and now I have no database. Where can I find my old database?

What version of postgres did you have before?
If it wasn't 8.4 then you won't be able to use your old database unless you made a backup of it first?
If not, you'll need to re-install 8.3 (or whatever you had before) and make a backup of your database (File > Backup) then re-install 8.4 and restore your backup.

Alternatively, you can create a new database and re-import your hands.