Thank you for trying Notezilla .
The master password cannot be retrieved. So the sticky notes cannot be retrieved. However, you can reset the master password. Once you reset, you will be able to delete those notes.
Click on the Forgot Password link shown below to reset the master password. To access Notezilla 's Preferences, right click on Notezilla icon and choose Preferences from the menu. Then click on Advanced button and then click on Master password button.