Notezilla stores data in Notes8.db. Open the folder %appdata%\Conceptworld\Notezilla in Windows Explorer. To do this, copy this path %appdata%\Conceptworld\Notezilla and run from start menu or open in Windows Explorer. You will be able to see the file Notes8.db. But you will not be able to access the Windows sticky notes as by just opening that file as it is in proprietary format.
To get those notes, you can install Notezilla on another system, copy Notes8.db file on that computer in the same folder of that computer (%appdata%\Conceptworld\Notezilla) and Run Notezilla to access your notes.