You can make a new database and start fresh. Here's how to do it:
Click File >>> Maintain database names
Click Add and you will see a new blank database appear under your current ones on the list. Name the new database, put a check mark on Dflt for you're new database (This will make your new database the primary one and open it automatically when you start poker tracker).
Next, under DB File/DB Name/DSN click the scrolldown box next to your new database and select "Create a New, Empty Access Database"
Click the OK button and choose which options you would like and thats it.